A study of the metabolism of L-alpha gamma-diaminobutyric acid in a Xanthomonas species.
1. l-alphagamma-Diaminobutyric acid is metabolized in Xanthomonas sp. to aspartic beta-semialdehyde, aspartic acid and oxaloacetic acid. 2. Aspartic beta-semialdehyde is formed from diaminobutyric acid by a pyruvate-dependent gamma-transamination. 3. The transaminase has a pH optimum of 9 and exhibits a high degree of substrate specificity, as analogues of diaminobutyric acid and pyruvate are inert in the system. The transaminase is inhibited by carbonyl-binding agents such as hydroxylamine. 4. Aspartic acid is formed from aspartic beta-semialdehyde by an NAD(+)-dependent dehydrogenation. 5. The dehydrogenase has a pH optimum of 8.5 and is a thiol enzyme. It is specific for aspartic beta-semialdehyde but analogues of NAD(+) such as 3-acetylpyridine-adenine dinucleotide and deamino-NAD are partly active in the system. 6. The significance of these reactions is discussed in relation to diaminobutyric acid metabolism in plants and mammalian systems.
D000613:Aminobutyrates / Q000378:metabolism*; D001223:Aspartate-Semialdehyde Dehydrogenase / Q000378:metabolism; D001224:Aspartic Acid / Q000096:biosynthesis; D006863:Hydrogen-Ion Concentration; D009243:NAD / Q000378:metabolism; D010071:Oxaloacetates / Q000096:biosynthesis; D000637:Transaminases / Q000378:metabolism; D014974:Xanthomonas / Q000378:metabolism*
D000613:Aminobutyrates; D010071:Oxaloacetates; D009243:NAD; D001224:Aspartic Acid; D001223:Aspartate-Semialdehyde Dehydrogenase; D000637:Transaminases