Reaction: (1) L-threonine = glycine + acetaldehyde
(2) L-allo-threonine = glycine + acetaldehyde
Other name(s): LtaE
Systematic name: L-threonine/L-allo-threonine acetaldehyde-lyase (glycine-forming)
Comments: Requires pyridoxal phosphate. The low-specificity L-threonine aldolase can act on both L-threonine and L-allo-threonine [1,2]. The enzyme from Escherichia coli can also act on L-threo-phenylserine and L-erythro-phenylserine [4]. The enzyme can also catalyse the aldol condensation of glycolaldehyde and glycine to form 4-hydroxy-L-threonine, an intermediate of pyridoxal phosphate biosynthesis [3]. Different from EC 4.1.2.5, L-threonine aldolase, and EC 4.1.2.49, L-allo-threonine aldolase.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Yamada, H., Kumagai, H., Nagate, T. and Yoshida, H. Crystalline threonine aldolase from Candida humicola. Biochem. Biophys. Res. Commun. 39 (1970) 53-58. [PMID: 5438301]
2. Kumagai, H., Nagate, T., Yoshida, H. and Yamada, H. Threonine aldolase from Candida humicola. II. Purification, crystallization and properties. Biochim. Biophys. Acta 258 (1972) 779-790. [PMID: 5017702]
3. Liu, J.Q., Nagata, S., Dairi, T., Misono, H., Shimizu, S. and Yamada, H. The GLY1 gene of Saccharomyces cerevisiae encodes a low-specific L-threonine aldolase that catalyzes cleavage of L-allo-threonine and L-threonine to glycine—expression of the gene in Escherichia coli and purification and characterization of the enzyme. Eur. J. Biochem. 245 (1997) 289-293. [PMID: 9151955]
4. Liu, J.Q., Dairi, T., Itoh, N., Kataoka, M., Shimizu, S. and Yamada, H. Gene cloning, biochemical characterization and physiological role of a thermostable low-specificity L-threonine aldolase from Escherichia coli. Eur. J. Biochem. 255 (1998) 220-226. [PMID: 9692922]
5. Kim, J., Kershner, J.P., Novikov, Y., Shoemaker, R.K. and Copley, S.D. Three serendipitous pathways in E. coli can bypass a block in pyridoxal-5'-phosphate synthesis. Mol. Syst. Biol. 6 (2010) 436. [PMID: 21119630]