Reaction: 2 S-adenosyl-L-methionine + C30 botryococcene = 2 S-adenosyl-L-homocysteine + 3,20-dimethyl-1,2,21,22-tetradehydro-2,3,20,21-tetrahydrobotryococcene (overall reaction)
(1a) S-adenosyl-L-methionine + C30 botryococcene = S-adenosyl-L-homocysteine + 3-methyl-1,2-didehydro-2,3-dihydrobotryococcene
(1b) S-adenosyl-L-methionine + 3-methyl-1,2-didehydro-2,3-dihydrobotryococcene = S-adenosyl-L-homocysteine + 3,20-dimethyl-1,2,21,22-tetradehydro-2,3,20,21-tetrahydrobotryococcene
(2a) S-adenosyl-L-methionine + C30 botryococcene = S-adenosyl-L-homocysteine + 20-methyl-21,22-didehydro-20,21-dihydrobotryococcene
(2b) S-adenosyl-L-methionine + 20-methyl-21,22-didehydro-20,21-dihydrobotryococcene = S-adenosyl-L-homocysteine + 3,20-dimethyl-1,2,21,22-tetradehydro-2,3,20,21-tetrahydrobotryococcene
For diagram of reaction click here.
Glossary: C30 botryococcene = (10S,13R)-10-ethenyl-2,6,10,13,17,21-hexamethyldocosa-2,5,11,16,20-pentaene
3-methyl-1,2-didehydro-2,3-dihydrobotryococcene = showacene
20-methyl-21,22-didehydro-20,21-dihydrobotryococcene = isoshowacene
Other name(s): TMT-3
Systematic name: S-adenosyl-L-methionine:botryococcene C-methyltransferase
Comments: Isolated from the green alga Botryococcus braunii BOT22. Shows a very weak activity with squalene.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Niehaus, T.D., Kinison, S., Okada, S., Yeo, Y.S., Bell, S.A., Cui, P., Devarenne, T.P. and Chappell, J. Functional identification of triterpene methyltransferases from Botryococcus braunii race B. J. Biol. Chem. 287 (2012) 8163-8173. [PMID: 22241476]