—CH=CH2 + CO2 + e- replaces the electron initially used.
An asterisk before 'EC' indicates that this is an amendment to an existing enzyme rather than a new enzyme entry.
Common name: glutamyl-tRNA reductase
Reaction: L-glutamate 1-semialdehyde + NADP+ + tRNAGlu = L-glutamyl-tRNAGlu + NADPH + H+
For diagram click here.
Systematic name: L-glutamate-semialdehyde: NADP+ oxidoreductase (L-glutamyl-tRNAGlu-forming)
Comments: This enzyme forms part of the pathway for the biosynthesis of 5-aminolevulinate from glutamate, known as the C5 pathway. The route shown in the diagram is used in most eubacteria, and in all archaebacteria, algae and plants. However, in the α-proteobacteria, EC 2.3.1.37, 5-aminolevulinate synthase, is used in an alternative route to produce the product 5-aminolevulinate from succinyl-CoA and glycine. This route is found in the mitochondria of fungi and animals, organelles that are considered to be derived from an endosymbiotic α-proteobacterium. Although higher plants do not possess EC 2.3.1.37, the protistan Euglena gracilis possesses both the C5 pathway and EC 2.3.1.37.
References:
1. von Wettstein, D., Gough, S. and Kannangara, C.G. Chlorophyll biosynthesis. Plant Cell 7 (1995) 1039-1057. [PMID: 12242396]
2. Pontoppidan, B. and Kannangara, C.G. Purification and partial characterisation of barley glutamyl-tRNAGlu reductase, the enzyme that directs glutamate to chlorophyll biosynthesis. Eur. J. Biochem. 225 (1994) 529-537. [PMID: 7957167]
3. Schauer, S., Chaturvedi, S., Randau, L., Moser, J., Kitabatake, M., Lorenz, S., Verkamp, E., Schubert, W.D., Nakayashiki, T., Murai, M., Wall, K., Thomann, H.-U., Heinz, D.W., Inokuchi, H, Söll, D. and Jahn, D. Escherichia coli glutamyl-tRNA reductase. Trapping the thioester intermediate. J. Biol. Chem. 277 (2002) 48657-48663. [PMID: 12370189]
Common name: 2'-hydroxydaidzein reductase
Reaction: 2'-hydroxy-2,3-dihydrodaidzein + NADP+ = 2'-hydroxydaidzein + NADPH + H+
For diagram click here.
Other name(s): NADPH:2'-hydroxydaidzein oxidoreductase; HDR; 2'-hydroxydihydrodaidzein:NADP+ 2'-oxidoreductase
Systematic name: 2'-hydroxy-2,3-dihydrodaidzein:NADP+ 2'-oxidoreductase
Comments: In the reverse reaction, the 2'-hydroxyisoflavone (2'-hydroxydaidzein) is reduced to an isoflavanone. Also acts on 2'-hydroxyformononetin and to a small extent on 2'-hydroxygenistein. Involved in the biosynthesis of the phytoalexin glyceollin. The isoflavones biochanin A, daidzein and genestein as well as the flavonoids apigenin, kaempferol and quercetin do not act as substrates.
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, CAS registry number: 126125-01-7
References:
1. Fischer, D., Ebenau-Jehle, C. and Grisebach, H. Phytoalexin synthesis in soybean: purification and characterization of NADPH:2'-hydroxydaidzein oxidoreductase from elicitor-challenged soybean cell cultures. Arch. Biochem. Biophys. 276 (1990) 390-395. [PMID: 2306102]
Common name: anthocyanidin reductase
Reaction: a flavan-3-ol + 2 NAD(P)+ = an anthocyanidin + 2 NAD(P)H + H+
For diagram click here.
Other name(s): AtANR; MtANR
Systematic name: flavan-3-ol:NAD(P)+ oxidoreductase
Comments: Forms 2,3-cis-flavan-3-ols. The isomeric 2,3-trans-flavan-3-ols are formed from flavan-3,4-diols by EC 1.17.1.3 leucoanthocyanidin reductase. While the enzyme from the legume Medicago truncatula (MtANR) uses both NADPH and NADH as reductant, that from the crucifer Arabidopsis thaliana (AtANR) uses only NADPH. Also, while the substrate preference of MtANR is cyanidin>pelargonidin>delphinidin, the reverse preference is found with AtANR.
CAS registry number: 93389-48-1
References:
1. Xie, D.Y., Sharma, S.B., Paiva, N.L., Ferreira, D. and Dixon, R.A. Role of anthocyanidin reductase, encoded by BANYULS in plant flavonoid biosynthesis. Science 299 (2003) 396-399. [PMID: 12532018]
2. Xie, D.Y., Sharma, S.B. and Dixon, R.A. Anthocyanidin reductases from Medicago truncatula and Arabidopsis thaliana. Arch. Biochem. Biophys. 422 (2004) 91-102. [PMID: 14725861]
Common name: coproporphyrinogen dehydrogenase
Reaction: coproporphyrinogen-III + 2 S-adenosyl-L-methionine = protoporphyrinogen IX + 2 CO2 + 2 L-methionine + 2 5'-deoxyadenosine
For diagram click here.
Other name(s): oxygen-independent coproporphyrinogen-III oxidase; HemN; radical SAM enzyme; coproporphyrinogen III oxidase
Systematic name: coproporphyrinogen-III:S-adenosyl-L-methionine oxidoreductase (decarboxylating)
Comments: This enzyme differs from EC 1.3.3.3, coproporphyrinogen oxidase, by using S-adenosyl-L-methionine (AdoMet) instead of oxygen as oxidant. It occurs mainly in bacteria, whereas eukaryotes use the oxygen-dependent oxidase. The reaction starts by using an electron from the reduced form of the enzyme's [4Fe-4S] cluster to split AdoMet into methionine and the radical 5'-deoxyadenosin-5'-yl. This radical initiates attack on the 2-carboxyethyl groups, leading to their conversion into vinyl groups. This conversion, —· CH-CH2-COO- —CH=CH2 + CO2 + e- replaces the electron initially used.
References:
1. Layer, G., Verfürth, K., Mahlitz, E. and Jahn, D. Oxygen-independent coproporphyrinogen-III oxidase HemN from Escherichia coli. J. Biol. Chem. 277 (2002) 34136-34142 [PMID: 12114526]
2. Layer, G., Moser, J., Heinz, D.W., Jahn, D. and Schubert, W.D. Crystal structure of coproporphyrinogen III oxidase reveals cofactor geometry of Radical SAM enzymes. EMBO J. 22 (2003) 6214-6224. [PMID: 14633981]
Common name: thiosulfate dehydrogenase (quinone)
Reaction: 2 thiosulfate + 2 6-decylubiquinone = tetrathionate + 2 6-decylubiquinol
Other name(s): thiosulfate:quinone oxidoreductase; thiosulphate:quinone oxidoreductase; thiosulfate oxidoreductase, tetrathionate-forming; TQO
Systematic name: thiosulfate:6-decylubiquinone oxidoreductase
Comments: The reaction can also proceed with ferricyanide as the electron acceptor, but more slowly. Unlike EC 1.8.2.2, thiosulfate dehydrogenase, this enzyme cannot utilize cytochrome c as an acceptor.
References:
1. Müller, F.H., Bandeiras, T.M., Urich, T., Teixeira, M., Gomes, C.M. and Kletzin, A. Coupling of the pathway of sulfur oxidation to dioxygen reduction: characterization of a novel membrane-bound thiosulfate:quinone oxidoreductase. Mol. Microbiol. 53 (2004) 1147-1160. [PMID: 15306018]
Common name: peroxiredoxin
Reaction: 2 R'-SH + ROOH = R'-S-S-R' + H2O + ROH
For diagram click here
Other name(s): thioredoxin peroxidase; tryparedoxin peroxidase; alkyl hydroperoxide reductase C22; AhpC; TrxPx; TXNPx; Prx; PRDX
Systematic name: thiol-containing-reductant:hydroperoxide oxidoreductase
Comments: Peroxiredoxins (Prxs) are a ubiquitous family of antioxidant proteins. They can be divided into three classes: typical 2-Cys, atypical 2-Cys and 1-Cys peroxiredoxins [1]. The peroxidase reaction comprises two steps centred around a redox-active cysteine called the peroxidatic cysteine. All three peroxiredoxin classes have the first step in common, in which the peroxidatic cysteine attacks the peroxide substrate and is oxidized to S-hydroxycysteine (a sulfenic acid) (see mechanism). The second step of the peroxidase reaction, the regeneration of cysteine from S-hydroxycysteine, distinguishes the three peroxiredoxin classes. For typical 2-Cys Prxs, in the second step, the peroxidatic S-hydroxycysteine from one subunit is attacked by the 'resolving' cysteine located in the C-terminus of the second subunit, to form an intersubunit disulfide bond, which is then reduced by one of several cell-specific thiol-containing reductants (R'-SH) (e.g. thioredoxin, AhpF, tryparedoxin or AhpD), completing the catalytic cycle. In the atypical 2-Cys Prxs, both the peroxidatic cysteine and its resolving cysteine are in the same polypeptide, so their reaction forms an intrachain disulfide bond [1]. To recycle the disulfide, known atypical 2-Cys Prxs appear to use thioredoxin as an electron donor [3]. The 1-Cys Prxs conserve only the peroxidatic cysteine, so that its oxidized form is directly reduced to cysteine by the reductant molecule [4].
References:
1. Wood, Z.A., Schröder, E., Harris, J.R. and Poole, L.B. Structure, mechanism and regulation of peroxiredoxins. Trends Biochem. Sci. 28 (2003) 32-40.
2. Hofmann, B., Hecht, H.J. and Flohé, L. Peroxiredoxins. Biol. Chem. 383 (2002) 347-364. [PMID: 12033427]
3. Seo, M.S., Kang, S.W., Kim, K., Baines, I.C., Lee, T.H. and Rhee, S.G. Identification of a new type of mammalian peroxiredoxin that forms an intramolecular disulfide as a reaction intermediate. J. Biol. Chem. 275 (2000) 20346-20354. [PMID: 10751410]
4. Choi, H.J., Kang, S.W., Yang, C.H., Rhee, S.G. and Ryu, S.E. Crystal structure of a novel human peroxidase enzyme at 2.0 Å resolution. Nat. Struct. Biol. 5 (1998) 400-406. [PMID: 9587003]
Common name: flavanone 3-dioxygenase
Reaction: a flavanone + 2-oxoglutarate + O2 = a dihydroflavonol + succinate + CO2
See diagram for reaction in aromadendrin or taxifolin biosynthesis.
Other name(s): naringenin 3-hydroxylase; flavanone 3-hydroxylase; flavanone 3β-hydroxylase; flavanone synthase I; (2S)-flavanone 3-hydroxylase; naringenin,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)
Systematic name: flavanone,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)
Comments: Requires Fe2+ and ascorbate.
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, CAS registry number: 75991-43-4
References: (if your browser cannot recognise unicode the author is Lukacin with a hacek over the c)
1. Forkmann, G., Heller, W. and Grisebach, H. Anthocyanin biosynthesis in flowers of Matthiola incana flavanone 3- and flavonoid 3'-hydroxylases. Z. Naturforsch. C: Biosci. 35 (1980) 691-695.
2. Wellmann, F., Matern, U. and Lukačin, R. Significance of C-terminal sequence elements for Petunia flavanone 3β-hydroxylase activity. FEBS Lett. 561 (2004) 149-154. [PMID: 15013767]
Common name: flavone synthase
Reaction: a flavanone + 2-oxoglutarate + O2 = a flavone + succinate + CO2 + H2O
See diagram for reaction in apigenin or luteolin biosynthesis.
Other Name(s): flavone synthase I; FNS I
Systematic name: flavanone,2-oxoglutarate:oxygen oxidoreductase (dehydrating)
Comments: Requires ascorbate for full activity and Fe2+.
CAS registry number: 138263-98-6
References: (if your browser cannot recognise unicode the author is Lukacin with a hacek over the c)
1. Martens, S., Forkmann, G., Matern, U. and Lukačin, R. Cloning of parsley flavone synthase I. Phytochemistry 58 (2001) 43-46. [PMID: 11524111]
2. Lukačin, R., Matern, U., Junghanns, K.T., Heskamp, M.L., Britsch, L., Forkmann, G. and Martens, S. Purification and antigenicity of flavone synthase I from irradiated parsley cells. Arch. Biochem. Biophys. 393 (2001) 177-183. [PMID: 11516175]
3. Martens, S., Forkmann, G., Britsch, L., Wellmann, F., Matern, U. and Lukačin, R. Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley. FEBS Lett. 544 (2003) 93-98. [PMID: 12782296]
Common name: flavonol synthase
Reaction: a dihydroflavonol + 2-oxoglutarate + O2 = a flavonol + succinate + CO2 + H2O
See diagram for reaction in quercetin or kaempferol or myricetin biosynthesis.
Other Name(s): flavonoid 2-oxoglutarate-dependent dioxygenase; FLS
Systematic name: dihydroflavonol,2-oxoglutarate:oxygen oxidoreductase
Comments: In addition to the desaturation of (2R,3R)-dihydroflavonols to flavonols, the enzyme from the satsuma Citrus unshiu also has a non-specific activity that trans-hydroxylates the flavanones (2S)-naringenin and the unnatural (2R)-naringenin at C-3 to kaempferol and (2R,3R)-dihydrokaempferol, respectively [2]. Requires Fe2+.
CAS registry number: 146359-76-4
References: (if your browser cannot recognise unicode the author is Lukacin with a hacek over the c)
1. Wellmann, F., Lukačin, R., Moriguchi, T., Britsch, L., Schiltz, E. and Matern, U. Functional expression and mutational analysis of flavonol synthase from Citrus unshiu. Eur. J. Biochem. 269 (2002) 4134-4142. [PMID: 12180990]
2. Lukačin, R., Wellmann, F., Britsch, L., Martens, S. and Matern, U. Flavonol synthase from Citrus unshiu is a bifunctional dioxygenase. Phytochemistry 62 (2003) 287-292. [PMID: 12620339]
3. Martens, S., Forkmann, G., Britsch, L., Wellmann, F., Matern, U. and Lukačin, R. Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley. FEBS Lett. 544 (2003) 93-98. [PMID: 12782296]
4. Turnbull, J.J., Nakajima, J., Welford, R.W., Yamazaki, M., Saito, K. and Schofield, C.J. Mechanistic studies on three 2-oxoglutarate-dependent oxygenases of flavonoid biosynthesis: anthocyanidin synthase, flavonol synthase, and flavanone 3β-hydroxylase. J. Biol. Chem. 279 (2004) 1206-1216. [PMID: 14570878]
Common name: glyceollin synthase
Reaction: 2-(or 4-)dimethylallyl-(6aS,11aS)-3,6a,9-trihydroxypterocarpan + NADPH + H+ + O2 = glyceollin + NADP+ + 2 H2O
For diagram click here.
Other Name(s): dimethylallyl-3,6a,9-trihydroxypterocarpan cyclase
Systematic name: 2-(or 4-)dimethylallyl-(6aS,11aS)-3,6a,9-trihydroxypterocarpan,NADPH:oxygen oxidoreductase (cyclizing)
Comments: A heme-thiolate protein (P-450). Glyceollins II and III are formed from 2-dimethylallyl-(6aS,11aS)-3,6a,9-trihydroxypterocarpan whereas glyceollin I is formed from the 4-isomer.
References:
1. Welle, R. and Grisebach, H. Induction of phytoalexin synthesis in soybean: enzymatic cyclization of prenylated pterocarpans to glyceollin isomers. Arch. Biochem. Biophys. 263 (1988) 191-198. [PMID: 3369863]
Common name: 2-hydroxyisoflavanone synthase
Reaction: apigenin + 2 NADPH + 2 H+ + O2 = 2-hydroxy-2,3-dihydrogenistein + 2 NADP+ + H2O
See diagram for reaction in genistein or daidzein biosynthesis.
Other Name(s): 2-HIS
Systematic name: apigenin,NADPH:oxygen oxidoreductase (isoflavanone-forming)
Comments: A heme-thiolate protein (P-450). EC 4.2.1.105, 2-hydroxyisoflavanone dehydratase, acts on 2-hydroxy-2,3-dihydrogenistein with loss of water and formation of genistein. This may occur spontaneously.
References:
1. Kochs. G. and Grisebach, H. Enzymic synthesis of isoflavones. Eur. J. Biochem. 155 (1986) 311-318. [PMID: 3956488]
2. Steele, C. L., Gijzen, M., Qutob, D. and Dixon, R.A. Molecular characterization of the enzyme catalyzing the aryl migration reaction of isoflavonoid biosynthesis in soybean. Arch. Biochem. Biophys. 367 (1999) 146-150. [PMID: 10375412]
Common name: licodione synthase
Reaction: liquiritigenin + NADPH + H+ + O2 = licodione + NADP+ + H2O
For diagram click here.
Glossary: licodione = 1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)propane-1,3-dione
Systematic name: liquiritigenin,NADPH:oxygen oxidoreductase (licodione-forming)
Comments: A heme-thiolate protein (P-450). It probably forms 2-hydroxyliquiritigenin which spontaneously forms licodione. NADH can act instead of NADPH, but more slowly.
CAS registry number: 157972-05-9
References:
1. Otani, K., Takahashi, T., Furuya, T. and Ayabe, S. Licodione synthase, a cytochrome P450 monooxygenase catalyzing 2-hydroxylation of 5-deoxyflavanone, in cultured Glycyrrhiza echinata L. cells. Plant Physiol. 105 (1994) 1427-1432. [PMID: 12232298]
2. Akashi, T., Aoki, T. and Ayabe, S. Identification of a cytochrome P450 cDNA encoding (2S)-flavanone 2-hydroxylase of licorice (Glycyrrhiza echinata L.; Fabaceae) which represents licodione synthase and flavone synthase II. FEBS Lett. 431 (1998) 287-290. [PMID: 9708921]
Common name: flavonoid 3',5'-hydroxylase
Reaction: (1) a flavanone + NADPH + H+ + O2 = a 3'-hydroxyflavanone + NADP+ + H2O
(2) a 3'-hydroxyflavanone + NADPH + H+ + O2 = a 3',5'-dihydroxyflavanone + NADP+ + H2O
See diagram for reaction in ampelopsin or dihydrotricetin or taxifolin biosynthesis.
Other Name(s): F3'5'H; F3',5'H
Systematic name: flavanone,NADPH:oxygen oxidoreductase
Comments: A heme-thiolate protein (P-450). The 3',5'-dihydroxyflavanone is formed via the 3'-hydroxyflavanone. In Petunia hybrida the enzyme acts on naringenin, eriodictyol, dihydroquercetin (taxifolin) and dihydrokaempferol (aromadendrin). The enzyme catalyses the hydroxylation of 5,7,4'-trihydroxyflavanone (naringenin) at either the 3' position to form eriodictyol or at both the 3' and 5' positions to form 5,7,3',4',5'-pentahydroxyflavanone (dihydrotricetin). The enzyme also catalyses the hydroxylation of 3,5,7,3',4'-pentahydroxyflavanone (taxifolin) at the 5' position, forming ampelopsin. NADH is not a good substitute for NADPH.
CAS registry number: 94047-23-1
References:
1. Menting, J., Scopes, R.K. and Stevenson, T.W. Characterization of flavonoid 3',5'-hydroxylase in microsomal membrane fraction of Petunia hybrida flowers. Plant Physiol. 106 (1994) 633-642. [PMID: 12232356]
2. Shimada, Y., Nakano-Shimada, R., Ohbayashi, M., Okinaka, Y., Kiyokawa, S. and Kikuchi, Y. Expression of chimeric P450 genes encoding flavonoid-3',5'-hydroxylase in transgenic tobacco and petunia plants. FEBS Lett. 461 (1999) 241-245. [PMID: 10567704]
3. de Vetten, N., ter Horst, J., van Schaik, H.P., de Boer, A., Mol, J. and Koes, R. A cytochrome b5 is required for full activity of flavonoid 3',5'-hydroxylase, a cytochrome P450 involved in the formation of blue flower colors. Proc. Natl. Acad. Sci. USA 96 (1999) 778-783. [PMID: 9892710]
Common name: [formate-C-acetyltransferase]-activating enzyme
Reaction: S-adenosyl-L-methionine + dihydroflavodoxin + [formate C-acetyltransferase]-glycine = 5'-deoxyadenosine + L-methionine + flavodoxin semiquinone +[formate C-acetyltransferase]-glycin-2-yl radical
Other name(s): PFL activase; PFL-glycine:S-adenosyl-L-methionine H transferase (flavodoxin-oxidizing, S-adenosyl-L-methionine-cleaving); formate acetyltransferase activating enzyme; formate acetyltransferase-glycine dihydroflavodoxin:S-adenosyl-L-methionine oxidoreductase (S-adenosyl-L-methionine cleaving)
Systematic name: [formate C-acetyltransferase]-glycine dihydroflavodoxin:S-adenosyl-L-methionine oxidoreductase (S-adenosyl-L-methionine cleaving)
Comments: An iron-sulfur protein. A single glycine residue in EC 2.3.1.54, formate C-acetyltransferase, is oxidized to the corresponding radical by transfer of H from its CH2 to AdoMet with concomitant cleavage of the latter. The reaction requires Fe2+. The first stage is reduction of the AdoMet to give methionine and the 5'-deoxyadenosin-5-yl radical, which then abstracts a hydrogen radical from the glycine residue.
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, CAS registry number: 206367-15-9
References:
1. Frey, M., Rothe, M., Wagner, A.F.V. and Knappe, J. Adenosylmethionine-dependent synthesis of the glycyl radical in pyruvate formate-lyase by abstraction of the glycine C-2 pro-S hydrogen atom. J. Biol. Chem. 269 (1994) 12432-12437. [PMID: 8175649]
2. Wagner, A.F.V., Frey, M., Neugebauer, F.A., Schäfer, W. and Knappe, J. The free radical in pyruvate formate-lyase is located on glycine-734. Proc. Natl Acad. Sci. USA 89 (1992) 996-1000. [PMID: 1310545]
3. Frey, P.A. Radical mechanisms in enzymatic catalysis. Annu. Rev. Biochem. 70 (2001) 121-148. [PMID: 11395404]
Common name: vitexin 2"-O-rhamnoside 7-O-methyltransferase
Reaction: S-adenosyl-L-methionine + vitexin 2"-O-β-L-rhamnoside = S-adenosyl-L-homocysteine + 7-O-methylvitexin 2"-O-β-L-rhamnoside
For diagram click here.
Systematic name: S-adenosyl-L-methionine:vitexin-2"-O-β-L-rhamnoside 7-O-methyltransferase
Comments: The flavonoids vitexin and isovitexin 2"-O-arabinoside do not act as substrates for the enzyme from oats (Avena sativa).
References:
1. Knogge, W. and Weissenbock, G. Purification, characterization, and kinetic mechanism of S-adenosyl-L-methionine: vitexin 2"-O-rhamnoside 7-O-methyltransferase of Avena sativa L. Eur. J. Biochem. 140 (1984) 113-118. [PMID: 6705789]
Common name: isoliquiritigenin 2'-O-methyltransferase
Reaction: S-adenosyl-L-methionine + isoliquiritigenin = S-adenosyl-L-homocysteine + 2'-O-methylisoliquiritigenin
For diagram click here.
Glossary: isoliquiritigenin = 4,2',4'-trihydroxychalcone
Other name(s): chalcone OMT; CHMT
Systematic name: S-adenosyl-L-methionine:isoliquiritigenin 2'-O-methyltransferase
Comments: Not identical to EC 2.1.1.65, licodione 2'-O-methyltransferase [2]. While EC 2.1.1.154, isoliquiritigenin 2'-O-methyltransferase can use licodione as a substrate, EC 2.1.1.65 cannot use isoliquiritigenin as a substrate.
CAS registry number: 139317-14-9
References:
1. Maxwell, C.A., Edwards, R. and Dixon R.A. Identification, purification, and characterization of S-adenosyl-L-methionine: isoliquiritigenin 2'-O-methyltransferase from alfalfa (Medicago sativa L.). Arch. Biochem. Biophys. 293 (1992) 158-166. [PMID: 1731632]
2. Ichimura, M., Furuno, T., Takahashi, T., Dixon, R.A. and Ayabe, S. Enzymic O-methylation of isoliquiritigenin and licodione in alfalfa and licorice cultures. Phytochemistry 44 (1997) 991-995. [PMID: 9055445]
Common name: kaempferol 4'-O-methyltransferase
Reaction: S-adenosyl-L-methionine + kaempferol = S-adenosyl-L-homocysteine + kaempferide
For diagram click here.
Glossary: kaempferide = 3,5,7-trihydroxy-4'-methoxyflavone
Other name(s): S-adenosyl-L-methionine:flavonoid 4'-O-methyltransferase; F 4'-OMT
Systematic name: S-adenosyl-L-methionine:kaempferol 4'-O-methyltransferase
Comments: The enzyme acts on the hydroxy group in the 4'-position of some flavones, flavanones and isoflavones. Kaempferol, apigenin and kaempferol triglucoside are substrates, as is genistein, which reacts more slowly. Compounds with an hydroxy group in the 3' and 4' positions, such as quercetin and eriodictyol, do not act as substrates. Similar to EC 2.1.1.75, apigenin 4'-O-methyltransferase and EC 2.1.1.83, 3,7-dimethylquercitin 4'-O-methyltransferase.
References:
1. Curir, P., Lanzotti, V., Dolci, M., Dolci, P., Pasini, C. and Tollin, G. Purification and properties of a new S-adenosyl-L-methionine:flavonoid 4'-O-methyltransferase from carnation (Dianthus caryophyllus L.). Eur. J. Biochem. 270 (2003) 3422-3431. [PMID: 12899699]
Common name: 6'-deoxychalcone synthase
Reaction: 3 malonyl-CoA + 4-coumaroyl-CoA + NADPH + H+ = 4 CoA + isoliquiritigenin + 3 CO2 + NADP+ + H2O
For diagram click here.
Glossary: isoliquiritigenin = 4,2',4'-trihydroxychalcone
liquiritigenin = 7,4'-dihydroxyflavanone
Systematic name: malonyl-CoA:4-coumaroyl-CoA malonyltransferase (cyclizing, reducing)
Comments: Isoliquiritigenin is the precursor of liquiritigenin, a 5-deoxyflavanone.
CAS registry number: 114308-23-5
References:
1. Ayabe, S., Udagawa, A. and Furuya, T. NAD(P)H-dependent 6'-deoxychalcone synthase activity in Glycyrrhiza echinata cells induced by yeast extract. Arch. Biochem. Biophys. 261 (1988) 458-462. [PMID: 3355160]
Common name: anthocyanin 6"-O-malonyltransferase
Reaction: malonyl-CoA + an anthocyanidin 3-O-β-D-glucoside = CoA + an anthocyanidin 3-O-(6-O-malonyl-β-D-glucoside)
For diagram click here.
Other Name(s): Dv3MaT; malonyl-coenzymeA:anthocyanidin-3-O-β-D-glucoside 6"-O-malonyltransferase; 3MaT
Systematic name: malonyl-CoA:anthocyanidin-3-O-β-D-glucoside 6"-O-malonyltransferase
Comments: Acts on pelargonidin 3-O-glucoside in dahlia (Dahlia variabilis), delphinidin 3-O-glucoside, and on cyanidin 3-O-glucoside in transgenic petunia (Petunia hybrida).
References:
1. Suzuki, H., Nakayama, T., Yonekura-Sakakibara, K., Fukui, Y., Nakamura, N., Yamaguchi, M.A., Tanaka, Y., Kusumi, T. and Nishino, T. cDNA cloning, heterologous expressions, and functional characterization of malonyl-coenzyme A:anthocyanidin 3-O-glucoside-6"-O-malonyltransferase from dahlia flowers. Plant Physiol. 130 (2002) 2142-2151. [PMID: 12481098]
Common name: anthocyanin 5-O-glucoside 6'''-O-malonyltransferase
Reaction: malonyl-CoA + pelargonidin 3-O-(6-caffeoyl-β-D-glucoside) 5-O-β-D-glucoside = CoA + 4'''-demalonylsalvianin
For diagram click here.
Glossary: salvianin = pelargonidin 3-O-(6-caffeoyl-β-D-glucoside) 5-O-(4,6-di-O-malonyl-β-D-glucoside)
Other Name(s): Ss5MaT1
Systematic name: malonyl-CoA:pelargonidin-3-O-(6-caffeoyl-β-D-glucoside)-5-O-β-D-glucoside 6'''-O-malonyltransferase
Comments: Specific for the penultimate step in salvianin biosynthesis. The enzyme also catalyses the malonylation of shisonin to malonylshisonin [cyanidin 3-O-(6"-O-p-coumaryl-β-D-glucoside)-5-(6'''-O-malonyl-β-D-glucoside)]. The compounds 4'''-demalonylsalvianin, salvianin, pelargonidin 3,5-diglucoside and delphinidin 3,5-diglucoside cannot act as substrates.
References:
1. Suzuki, H., Nakayama, T., Yonekura-Sakakibara, K., Fukui, Y., Nakamura, N., Nakao, M., Tanaka, Y., Yamaguchi, M.A., Kusumi, T. and Nishino, T. Malonyl-CoA:anthocyanin 5-O-glucoside-6'''-O-malonyltransferase from scarlet sage (Salvia splendens) flowers. J. Biol. Chem. 276 (2001) 49013-49019. [PMID: 11598135]
Common name: flavonol-3-O-triglucoside O-coumaroyltransferase
Reaction: 4-coumaroyl-CoA + a flavonol 3-O-[β-D-glucosyl-(12)-β-D-glucosyl-(12)-β-D-glucoside] = CoA + a flavonol 3-O-[6-(4-coumaroyl)-β-D-glucosyl-(12)-β-D-glucosyl-(12)-β-D-glucoside]
For diagram click here.
Systematic name: 4-coumaroyl-CoA:flavonol-3-O-[β-D-glucosyl-(12)-β-D-glucosyl-(12)-β-D-glucoside] 6'''-O-4-coumaroyltransferase
Comments: Acylates kaempferol 3-O-triglucoside on the terminal glucosyl unit, almost certainly at C-6.
References:
1. Saylor, M.H. and Mansell, R.L. Hydroxycinnamoyl:coenzyme A transferase involved in the biosynthesis of kaempferol-3-(p-coumaroyl triglucoside) in Pisum sativum. Z. Naturforsch. [C] 32 (1977) 765-768. [PMID: 145116]
Common name: anthocyanidin 3-O-glucosyltransferase
Reaction: UDP-glucose + an anthocyanidin = UDP + an anthocyanidin 3-β-D-glucoside
For diagram click here.
Other name(s): 3-GT
Systematic name: UDP-glucose:anthocyanidin 3-O-β-D-glucosyltransferase
Comments: The anthocyanidin compounds cyanidin, delphinidin, peonidin and to a lesser extent pelargonidin can act as substrates. In conjunction with EC 1.14.11.19, leucocyanidin oxygenase, it is involved in the conversion of leucoanthocyanidin into anthocyanidin 3-glucoside. It may act on the pseudobase precursor of the anthocyanidin rather than the anthocyanidin itself [3].
References:
1. Kamsteeg, J., van Brederode, J. and van Nigtevecht, G. Identification and properties of UDP-glucose: cyanidin-3-O-glucosyltransferase isolated from petals of the red campion (Silene dioica). Biochem. Genet. 16 (1978) 1045-1058. [PMID: 751640]
2. Ford, C.M., Boss, P.K. and Høj, P.B. Cloning and characterization of Vitis vinifera UDP-glucose:flavonoid 3-O-glucosyltransferase, a homologue of the enzyme encoded by the maize Bronze-1 locus that may primarily serve to glucosylate anthocyanidins in vivo. J. Biol. Chem. 273 (1998) 9224-9233. [PMID: 9535914]
3. Nakajima, J., Tanaka, Y., Yamazaki, M. and Saito, K. Reaction mechanism from leucoanthocyanidin to anthocyanidin 3-glucoside, a key reaction for coloring in anthocyanin biosynthesis. J. Biol. Chem. 276 (2001) 25797-25803. [PMID: 11316805]
Common name: kaempferol 3-O-galactosyltransferase
Reaction: UDP-galactose + kaempferol = UDP + kaempferol 3-O-β-D-galactoside
For diagram click here.
Other name(s): F3GalTase
Systematic name: UDP-galactose:kaempferol 3-O-β-D-galactosyltransferase
Comments: Acts on the endogenous flavonols kaempferol and quercetin, to a lesser extent on myricetin and fisetin, and weakly on galangin and isorhamnetin. The reaction can occur equally well in both directions.
References:
1. Miller, K.D., Guyon, V., Evans, J.N., Shuttleworth, W.A. and Taylor, L.P. Purification, cloning, and heterologous expression of a catalytically efficient flavonol 3-O-galactosyltransferase expressed in the male gametophyte of Petunia hybrida. J. Biol. Chem. 274 (1999) 34011-34019. [PMID: 10567367]
Common name: cyanidin 3-O-rutinoside 5-O-glucosyltransferase
Reaction: UDP-glucose + cyanidin 3-O-rutinoside = UDP + cyanidin 3-O-rutinoside 5-O-β-D-glucoside
Other Name(s): UDP-glucose:cyanidin-3-rhamnosyl-(16)-glucoside-5-O-glucosyltransferase
For diagram click here.
Systematic name: UDP-glucose:cyanidin-3-O-β-L-rhamnosyl-(16)-β-D-glucoside 5-O-β-D-glucosyltransferase
Comments: Also acts on pelargonidin-3-rutinoside. The enzyme does not catalyse the glucosylation of the 5-hydroxy group of cyanidin-3-glucoside.
CAS registry number: 70248-66-7
References:
1. Kamsteeg, J., van Brederode, J. and van Nigtevecht, G. Identification, properties, and genetic control of UDP-glucose:cyanidin-3-rhamnosyl-(16)-glucoside-5-O-glucosyltransferase isolated from petals of the red campion (Silene dioica). Biochem Genet. 16 (1978) 1059-1071. [PMID: 751641]
Common name: flavanone 7-O-glucoside 2"-O-β-L-rhamnosyltransferase
Reaction: UDP-L-rhamnose + a flavanone 7-O-glucoside = UDP + a flavanone 7-O-[β-L-rhamnosyl-(12)-β-D-glucoside]
See diagram for reaction with 7-O--glucosides of naringenin or apigenin or luteolin.
Other name(s): UDP-rhamnose:flavanone-7-O-glucoside-2"-O-rhamnosyltransferase; 12 UDP-rhamnosyltransferase
Systematic name: UDP-L-rhamnose:flavanone-7-O-glucoside 2"-O-β-L-rhamnosyltransferase
Comments: Acts on the 7-O-glucoside of naringenin and hesperetin, also the flavone 7-O-glucosides of luteolin and apigenin.
References:
1. Bar-Peled, M., Lewinsohn, E., Fluhr, R. and Gressel, J. UDP-rhamnose:flavanone-7-O-glucoside-2"-O-rhamnosyltransferase. Purification and characterization of an enzyme catalyzing the production of bitter compounds in citrus. J. Biol. Chem. 266 (1991) 20953-20959. [PMID: 1939145]
Common name: flavonol 7-O-β-glucosyltransferase
Reaction: UDP-glucose + a flavonol = UDP + a flavonol 7-O-β-D-glucoside
For diagram click here.
Other name(s): UDP-glucose:flavonol 7-O-glucosyltransferase
Systematic name: UDP-glucose:flavonol 7-O-β-D-glucosyltransferase
Comments: Acts on the flavonols gossypetin (8-hydroxyquercetin) and to a lesser extent on quercetin, kaempferol and myricetin.
CAS registry number: 83682-90-0
References:
1. Stich, K., Halbwirth, H., Wurst, F. and Forkmann, G. UDP-glucose:flavonol 7-O-glucosyltransferase activity in flower extracts of Chrysanthemum segetum. Z. Naturforsch. [C] 52 (1997) 153-158. [PMID: 9167271]
Common name: anthocyanin 3'-O-β-glucosyltransferase
Reaction: UDP-glucose + an anthocyanin = UDP + an anthocyanin 3'-O-β-D-glucoside
For diagram click here.
Other name(s): UDP-glucose:anthocyanin 3'-O-glucosyltransferase; 3'GT
Systematic name: UDP-glucose:anthocyanin 3'-O-β-D-glucosyltransferase
Comments: This enzyme specifically glucosylates the 3'-hydroxy group of delphinidin-(3-O-glucosyl-5-O-(6-O-caffeoylglucosyl)-3'-O-(6-O-caffeoylglucoside)-type anthocyanins containing glucose groups at the 3 and 5 positions. Acts on delphinidin 3,5-di-O-glucoside in gentian (Gentiana triflora).
CAS registry number: 380231-41-4
References:
1. Fukuchi-Mizutani, M., Okuhara, H., Fukui, Y., Nakao, M., Katsumoto, Y., Yonekura-Sakakibara, K., Kusumi, T., Hase, T. and Tanaka, Y. Biochemical and molecular characterization of a novel UDP-glucose:anthocyanin 3'-O-glucosyltransferase, a key enzyme for blue anthocyanin biosynthesis, from gentian. Plant Physiol. 132 (2003) 1652-1663. [PMID: 12857844]
Common name: flavonol-3-O-glucoside glucosyltransferase
Reaction: UDP-glucose + a flavonol 3-O-β-D-glucoside = UDP + a flavonol 3-O-β-D-glucosyl-(12)-β-D-glucoside
See diagram for reaction with 3-O-β-D-glucosides of kaempferol or quercetin.
Systematic name: UDP-glucose:flavonol-3-O-glucoside 2"-O-β-D-glucosyltransferase
Comments: One of three specific glucosyltransferases in pea (Pisum sativum) that successively add a β-D-glucosyl group first to O-3 of kaempferol, and then to O-2 of the previously added glucosyl group giving the 3-O-sophoroside and then the 3-O-sophorotrioside (see also EC 2.4.1.91, flavonol 3-O-glucosyltransferase and EC 2.4.1.240, flavonol-3-O-glycoside glucosyltransferase). TDP-glucose can replace UDP-glucose as the glucose donor but the reaction proceeds more slowly.
References:
1. Jourdan, P.S. and Mansell, R.L. Isolation and partial characterization of three glucosyl transferases involved in the biosynthesis of flavonol triglucosides in Pisum sativum L. Arch. Biochem. Biophys. 213 (1982) 434-443. [PMID: 6462109]
Common name: flavonol-3-O-glycoside glucosyltransferase
Reaction: UDP-glucose + a flavonol 3-O-β-D-glucosyl-(12)-β-D-glucoside = UDP + a flavonol 3-O-β-D-glucosyl-(12)-β-D-glucosyl-(12)-β-D-glucoside
See diagram for reaction with 3-O-β-D-glucosyl-(12)-β-D-glucosides of kaempferol or quercetin.
Systematic name: UDP-glucose:flavonol-3-O-β-D-glucosyl-(12)-β-D-glucoside 2'''-O-β-D-glucosyltransferase
Comments: One of three specific glucosyltransferases in pea (Pisum sativum) that successively add a β-D-glucosyl group first to O-3 of kaempferol, and then to O-2 of the previously added glucosyl group giving the 3-O-sophoroside and then the 3-O-sophorotrioside (see also EC 2.4.1.91 flavonol 3-O-glucosyltransferase, and EC 2.4.1.239 flavonol-3-O-glucoside glucosyltransferase).
References:
1. Jourdan, P.S. and Mansell, R.L. Isolation and partial characterization of three glucosyl transferases involved in the biosynthesis of flavonol triglucosides in Pisum sativum L. Arch. Biochem. Biophys. 213 (1982) 434-443. [PMID: 6462109]
Common name: O-phosphoserine sulfhydrylase
Reaction: O-phospho-L-serine + hydrogen sulfide = L-cysteine + phosphate
Other name(s): O-phosphoserine(thiol)-lyase
Systematic name: O-phospho-L-serine:hydrogen-sulfide 2-amino-2-carboxyethyltransferase
Comments: A pyridoxal-phosphate protein. The enzyme from Aeropyrum pernix acts on both O-phospho-L-serine and O3-acetyl-L-serine, in contrast with EC 2.5.1.47, cysteine synthase, which acts only on O3-acetyl-L-serine.
References:
1. Mino, K. and Ishikawa, K. A novel O-phospho-L-serine sulfhydrylation reaction catalyzed by O-acetylserine sulfhydrylase from Aeropyrum pernix K1. FEBS Lett. 551 (2003) 133-138. [PMID: 12965218]
2. Mino, K. and Ishikawa, K. Characterization of a novel thermostable O-acetylserine sulfhydrylase from Aeropyrum pernix K1. J. Bacteriol. 185 (2003) 2277-2284. [PMID: 12644499]
3. Mino, K. and Ishikawa, K. Crystallization and preliminary X-ray diffraction analysis of O-acetylserine sulfhydrylase from Aeropyrum pernix K1. Acta Crystallogr. D Biol. Crystallogr. 59 (2003) 338-340. [PMID: 12554945]
Common name: N2-(2-carboxyethyl)arginine synthase
Reaction: D-glyceraldehdye 3-phosphate + L-arginine = N2-(2-carboxyethyl)-L-arginine + phosphate
For diagram click here.
Other name(s): CEAS; N2-(2-carboxyethyl)arginine synthetase; CEA synthetase
Systematic name: glyceraldhyde-3-phosphate:L-arginine N2-(2-hydroxy-3-oxopropyl) transferase (2-carboxyethyl-forming)
Comments: The enzyme requires thiamine diphosphate and catalyses the first step in the clavulanic-acid-biosynthesis pathway. The 2-hydroxy-3-oxo group transferred from glyceraldehyde 3-phosphate is isomerized during transfer to form the 2-carboxyethyl group.
References:
1. Caines, M.E.C., Elkins, J.M., Hewitson, K.S. and Schofield, C.J. Crystal structure and mechanistic implications of N2-(2-carboxyethyl)arginine synthase, the first enzymes in the clavulanic acid biosynthesis pathway. J. Biol. Chem. 279 (2004) 5685-5692. [PMID: 14623876]
2. Khaleeli, N., Li, R. and Townsend, C.A. Origin of the β-lactam carbons in clavulanic acid from an unusual thiamine pyrophosphate-mediated reaction. J. Am. Chem. Soc. 121 (1999) 9223-9224.
Common name: petromyzonol sulfotransferase
Reaction: 3'-phosphoadenylyl sulfate + 5α-cholan-3α,7α,12α,24-tetrol = adenosine 3',5'-bisphosphate + 5α-cholan-3α,7α,12α-triol 24-sulfate
For diagram click here.
Glossary: petromyzonol = 5α-cholan-3α,7α,12α,24-tetrol
3'-phosphoadenylyl sulfate
Other name(s): PZ-SULT
Systematic name: 3'-phosphoadenylyl-sulfate:5α-cholan-3α,7α,12α,24-tetrol sulfotransferase
Comments: The enzyme from the lamprey Petromyzon marinus can also use the corresponding 3-ketone as a substrate. It is stereoselective (5α-cholane) and regioselective, exhibiting a preference for an hydroxy group at C-24. The enzyme is inactive when allocholic acid, which has a carboxy group at C-24, is used as a substrate.
References:
1. Venkatachalam, K.V., Llanos, D.E., Karami, K.J. and Malinovskii, V.A. Isolation, partial purification, and characterization of a novel petromyzonol sulfotransferase from Petromyzon marinus (lamprey) larval liver. J. Lipid Res. 45 (2004) 486-495. [PMID: 14657197]
Common name: inositol-phosphate phosphatase
Reaction: myo-inositol phosphate + H2O = myo-inositol + phosphate
For diagram click here.
Other name(s): myo-inositol-1(or 4)-monophosphatase; inositol 1-phosphatase; L-myo-inositol-1-phosphate phosphatase; myo-inositol 1-phosphatase; inositol phosphatase; inositol monophosphate phosphatase; inositol-1(or 4)-monophosphatase; myo-inositol-1(or 4)-phosphate phosphohydrolase; myo-inositol monophosphatase; myo-inositol-1-phosphatase
Systematic name: myo-inositol-phosphate phosphohydrolase
Comments: Acts on five of the six isomers of myo-inositol phosphate, all except myo-inositol 2-phosphate, but does not act on myo-inositol bearing more than one phosphate group. It also acts on adenosine 2'-phosphate (but not the 3'- or 5'- phosphates), sn-glycerol 3-phosphate and glycerol 2-phosphate. Two isoforms are known [4].
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, PDB, CAS registry number: 37184-63-7
References:
1. Eisenberg, F., Jr. D-Myoinositol 1-phosphate as product of cyclization of glucose 6-phosphate and substrate for a specific phosphatase in rat testis. J. Biol. Chem. 242 (1967) 1375-1382. [PMID: 4290245]
2. Gee, N.S., Ragan, C.I., Watling, K.J., Aspley, S., Jackson, R.G., Reid, G.G., Gani, D. and Shute, J.K. The purification and properties of myo-inositol monophosphatase from bovine brain. Biochem. J. 249 (1988) 883-889. [PMID: 2833231]
3. Hallcher, L.M. and Sherman, W.R. The effects of lithium ion and other agents on the activity of myo-inositol-1-phosphatase from bovine brain. J. Biol. Chem. 255 (1980) 10896-10901. [PMID: 6253491]
4. Yoshikawa, T., Turner, G., Esterling, L.E., Sanders, A.R. and Detera-Wadleigh, S.D. A novel human myo-inositol monophosphatase gene, IMP.18p, maps to a susceptibility region for bipolar disorder. Mol. Psychiatry 2 (1997) 393-397. [PMID: 9322233]
5. Woscholski, R. and Parker, P.J. Inositol phosphatases: constructive destruction of phosphoinositides and inositol phosphates. In: Cockcroft, S. (Ed.), Biology of Phosphoinositides, Oxford University Press, Oxford, 2000, pp. 320-338.
6. Ackermann, K.E., Gish, B.G., Honchar, M.P. and Sherman, W.R. Evidence that inositol 1-phosphate in brain of lithium-treated rats results mainly from phosphatidylinositol metabolism. Biochem. J. 242 (1987) 517-524. [PMID: 3036092]
Common name: pyridoxal phosphatase
Reaction: pyridoxal 5'-phosphate + H2O = pyridoxal + phosphate
Other name(s): vitamine B6 (pyridoxine) phosphatase; PLP phosphatase; vitamin B6-phosphate phosphatase; PNP phosphatase
Systematic name: pyridoxal-5'-phosphate phosphohydrolase
Comments: Requires Mg2+. This enzyme is specific for phosphorylated vitamin B6 compounds: it acts not only on pyridoxal phosphate (PLP), but also on pyridoxine phosphate (PNP), pyridoxamine phosphate (PMP), 4-pyridoxic acid phosphate and 4-deoxypyridoxine phosphate. This reaction can also be carried out by EC 3.1.3.1 (alkaline phosphatase) and EC 3.1.3.2 (acid phosphatase), but these enzymes have very broad substrate specificities.
References:
1. Fonda, M.L. Purification and characterization of vitamin B6-phosphate phosphatase from human erythrocytes. J. Biol. Chem. 267 (1992) 15978-15983. [PMID: 1322411]
2. Fonda, M.L. and Zhang, Y.N. Kinetic mechanism and divalent metal activation of human erythrocyte pyridoxal phosphatase. Arch. Biochem. Biophys. 320 (1995) 345-352. [PMID: 7625842]
3. Jang, Y.M., Kim, D.W., Kang, T.C., Won, M.H., Baek, N.I., Moon, B.J., Choi, S.Y. and Kwon, O.S. Human pyridoxal phosphatase. Molecular cloning, functional expression, and tissue distribution. J. Biol. Chem. 278 (2003) 50040-50046. [PMID: 14522954]
Common name: phosphoethanolamine/phosphocholine phosphatase
Reaction: (1) O-phosphoethanolamine + H2O = ethanolamine + phosphate
(2) phosphocholine + H2O = choline + phosphate
Other name(s): PHOSPHO1; 3X11A
Systematic name: phosphoethanolamine phosphohydrolase
Comments: Requires active site Mg2+ but also works, to a lesser extent, with Co2+ and Mn2+. The enzyme is highly specific for phosphoethanolamine and phosphocholine.
References:
1. Houston, B., Seawright, E., Jefferies, D., Hoogland, E., Lester, D., Whitehead, C. and Farquharson, C. Identification and cloning of a novel phosphatase expressed at high levels in differentiating growth plate chondrocytes. Biochim. Biophys. Acta 1448 (1999) 500-506. [PMID: 9990301]
2. Stewart, A.J., Schmid, R., Blindauer, C.A., Paisey, S.J. and Farquharson, C. Comparative modelling of human PHOSPHO1 reveals a new group of phosphatases within the haloacid dehalogenase superfamily. Protein Eng. 16 (2003) 889-895. [PMID: 14983068]
3. Roberts, S.J., Stewart, A.J., Sadler, P.J. and Farquharson C. Human PHOSPHO1 displays high specific phosphoethanolamine and phosphocholine phosphatase activities. Biochem. J. 382 (2004) 59-65. [PMID: 15175005]
[EC 3.2.1.148 Transferred entry: now EC 3.13.1.2, 5-deoxyribos-5-ylhomocysteinase (EC 3.2.1.148 created 1972 as EC 3.3.1.3, transferred 2001 to EC 3.2.1.148, deleted 2004)]
Common name: adenosylhomocysteine nucleosidase
Reaction: S-adenosyl-L-homocysteine + H2O = S-(5-deoxy-D-ribos-5-yl)-L-homocysteine + adenine
For diagram click here.
Other name(s): S-adenosylhomocysteine hydrolase; S-adenosylhomocysteine nucleosidase; 5'-methyladenosine nucleosidase; S-adenosylhomocysteine/5'-methylthioadenosine nucleosidase; AdoHcy/MTA nucleosidase
Systematic name: S-adenosyl-L-homocysteine homocysteinylribohydrolase
Comments: Also acts on S-methyl-5'-thioadenosine to give adenine and S-methyl-5-thioribose (cf. EC 3.2.2.16, methylthioadenosine nucleosidase).
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, PDB, CAS registry number: 9055-10-1
References:
1. Duerre, J.A. A hydrolytic nucleosidase acting on S-adenosylhomocysteine and on 5-methylthioadenosine. J. Biol. Chem. 237 (1962) 3737-3741.
2. Ferro, A.J., Barrett, A. and Shapiro, S.K. Kinetic properties and the effect of substrate analogues on 5'-methylthioadenosine nucleosidase from Escherichia coli. Biochim. Biophys. Acta 438 (1976) 487-494. [PMID: 782530]
Common name: methylthioadenosine nucleosidase
Reaction: S-methyl-5'-thioadenosine + H2O = S-methyl-5-thio-D-ribose + adenine
Other name(s): 5'-methylthioadenosine nucleosidase; MTA nucleosidase; MeSAdo nucleosidase; methylthioadenosine methylthioribohydrolase
Systematic name: S-methyl-5'-thioadenosine adeninehyrolase
Comments: Does not act on S-adenosylhomocysteine. cf. EC 3.2.2.9 adenosylhomocysteine nucleosidase.
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, PDB, CAS registry number: 50812-28-7
References:
1. Guranowski, A.B., Chiang, P.K. and Cantoni, G.L. 5'-Methylthioadenosine nucleosidase. Purification and characterization of the enzyme from Lupinus luteus seeds. Eur. J. Biochem. 114 (1981) 293-299. [PMID: 6783408]
*EC 3.3.1 Thioether and trialkylsulfonium hydrolases
Common name: adenosylhomocysteinase
Reaction: S-adenosyl-L-homocysteine + H2O = L-homocysteine + adenosine
For diagram click here.
Other name(s): S-adenosylhomocysteine synthase; S-adenosylhomocysteine hydrolase; S-adenosyl-L-homocysteine hydrolase; adenosylhomocysteine hydrolase; S-adenosylhomocysteinase; SAHase; AdoHcyase
Systematic name: S-adenosyl-L-homocysteine hydrolase
Comments: The enzyme contains one tightly bound NAD+ per subunit. This appears to bring about a transient oxidation at C-3' of the 5'-deoxyadenosine residue, thus labilizing the thioether bond [2] (for mechanism click here), cf. EC 5.5.1.4, inositol-3-phosphate synthase.
Links to other databases: BRENDA, EXPASY, GTD, KEGG, ERGO, PDB, CAS registry number: 9025-54-1
References:
1. de la Haba, G. and Cantoni, G.L. The enzymatic synthesis of S-adenosyl-L-homocysteine from adenosine and homocysteine. J. Biol. Chem. 234 (1959) 603-608.
2. Palmer, J.L. and Abeles, R.H. The mechanism of action of S-adenosylhomocysteinase. J. Biol. Chem. 254 (1979) 1217-1226. [PMID: 762125]
Common name: 5-deoxyribos-5-ylhomocysteinase
Reaction: S-(5-deoxyribos-5-yl)-L-homocysteine + H2O = D-ribose + L-homocysteine
Other name(s): ribosylhomocysteinase; S-ribosylhomocysteinase; S-ribosyl-L-homocysteine ribohydrolase
Systematic name: S-(5-deoxyribos-5-yl)-L-homocysteine hydrolase
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, CAS registry number: 37288-63-4
References:
1. Duerre, J.A. and Miller, C.H. Cleavage of S-ribosyl-L-homocysteine by extracts from Escherichia coli. J. Bacteriol. 91 (1966) 1210-1217. [PMID: 5326098]
[EC 4.2.1.86 Deleted entry: 16-dehydroprogesterone hydratase (reaction is identical to that of EC 4.2.1.98, 16α-hydroxyprogesterone dehydratase) (EC 4.2.1.86 created 1989, deleted 2004)]
Common name: 16α-hydroxyprogesterone dehydratase
Reaction: 16α-hydroxyprogesterone = 16,17-didehydroprogesterone + H2O
For diagram click here.
Other name(s): hydroxyprogesterone dehydroxylase; 16α-hydroxyprogesterone dehydroxylase; 16α-dehydroxylase
Systematic name: 16α-hydroxyprogesterone hydro-lyase
Comments: 16α-Hydroxypregnenolone is also a substrate.
Links to other databases: BRENDA, EXPASY, KEGG, ERGO, CAS registry number:
References:
1. Glass, T.L. and Lamppa, R.S. Purification and properties of 16α-hydroxyprogesterone dehydroxylase from Eubacterium sp. strain 144. Biochim. Biophys. Acta 837 (1985) 103-110. [PMID: 4052439]
Common name: 2-hydroxyisoflavanone dehydratase
Reaction: 2,7,4'-trihydroxyisoflavanone = daidzein + H2O
See diagram for reaction in genistein or daidzein biosynthesis.
Glossary: daidzein = 7,4'-dihydroxyisoflavone
Systematic name: 2,7,4'-trihydroxyisoflavanone hydro-lyase
Comments: Catalyses the final step in the formation of the isoflavonoid skeleton. The reaction also occurs spontaneously.
CAS registry number: 56022-25-4
References:
1. Hakamatsuka, T., Mori, K., Ishida, S., Ebizuka, Y and Sankawa, U. Purification of 2-hydroxyisoflavanone dehydratase from the cell cultures of Pueraria lobata. Phytochemistry 49 (1998) 497-505.
Common name: S-ribosylhomocysteine lyase
Reaction: S-(5-deoxy-D-ribos-5-yl)-L-homocysteine = L-homocysteine + (S)-4,5-dihydroxypentan-2,3-dione
For diagram click here.
Other name(s): S-ribosylhomocysteinase; LuxS
Systematic name: S-(5-deoxy-D-ribos-5-yl)-L-homocysteine homocysteine-lyase [(4S)-4,5-dihydroxypentan-2,3-dione-forming]
Comments: Contains Fe2+. The 4,5-dihydroxypentan-2,3-dione formed spontaneously cyclizes and combines with borate to form an autoinducer (AI-2) in the bacterial quorum-sensing mechanism, which is used by many bacteria to control gene expression in response to cell density [2].
References:
1. Zhu, J., Dizin, E., Hu, X., Wavbreille, A.S., Park, J. and Pei, D. S-Ribosylhomocysteinase (LuxS) is a mononuclear iron protein. Biochemistry 42 (2003) 4717-4726. [PMID: 12705835]
2. Miller, M.B. and Bassler, B.L. Quorum sensing in bacteria. Annu. Rev. Microbiol. 55 (2001) 165-199. [PMID: 11544353]