Reaction: L-2,4-diaminobutanoate + 2-oxoglutarate = L-aspartate 4-semialdehyde + L-glutamate
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Other name(s): L-2,4-diaminobutyrate:2-ketoglutarate 4-aminotransferase; 2,4-diaminobutyrate 4-aminotransferase; diaminobutyrate aminotransferase; DABA aminotransferase; DAB aminotransferase; EctB; diaminibutyric acid aminotransferase; L-2,4-diaminobutyrate:2-oxoglutarate 4-aminotransferase
Systematic name: L-2,4-diaminobutanoate:2-oxoglutarate 4-aminotransferase
Comments: A pyridoxal-phosphate protein that requires potassium for activity [4]. In the proteobacterium Acinetobacter baumannii, this enzyme is cotranscribed with the neighbouring ddc gene that also encodes EC 4.1.1.86, diaminobutyrate decarboxylase. Differs from EC 2.6.1.46, diaminobutyrate—pyruvate transaminase, which has pyruvate as the amino-group acceptor. This is the first enzyme in the ectoine-biosynthesis pathway, the other enzymes involved being EC 2.3.1.178, diaminobutyrate acetyltransferase and EC 4.2.1.108, ectoine synthase [3,4].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 196622-96-5
References:
1. Ikai, H. and Yamamoto, S. Identification and analysis of a gene encoding L-2,4-diaminobutyrate:2-ketoglutarate 4-aminotransferase involved in the 1,3-diaminopropane production pathway in Acinetobacter baumannii. J. Bacteriol. 179 (1997) 5118-5125. [PMID: 9260954]
2. Ikai, H. and Yamamoto, S. Two genes involved in the 1,3-diaminopropane production pathway in Haemophilus influenzae. Biol. Pharm. Bull. 21 (1998) 170-173. [PMID: 9514614]
3. Peters, P., Galinski, E.A. and Truper, H.G. The biosynthesis of ectoine. FEMS Microbiol. Lett. 71 (1990) 157-162.
4. Ono, H., Sawada, K., Khunajakr, N., Tao, T., Yamamoto, M., Hiramoto, M., Shinmyo, A., Takano, M. and Murooka, Y. Characterization of biosynthetic enzymes for ectoine as a compatible solute in a moderately halophilic eubacterium, Halomonas elongata. J. Bacteriol. 181 (1999) 91-99. [PMID: 9864317]
5. Kuhlmann, A.U. and Bremer, E. Osmotically regulated synthesis of the compatible solute ectoine in Bacillus pasteurii and related Bacillus spp. Appl. Environ. Microbiol. 68 (2002) 772-783. [PMID: 11823218]
6. Louis, P. and Galinski, E.A. Characterization of genes for the biosynthesis of the compatible solute ectoine from Marinococcus halophilus and osmoregulated expression in Escherichia coli. Microbiology 143 (1997) 1141-1149. [PMID: 9141677]