Two omega-amino acid transaminases from Bacillus cereus.
Bacillus cereus strain K-22 produced two distinct omega-amino acid transaminases, one catalyzing the transamination between beta-alanine and pyruvic acid and the other that between gamma-aminobutyric acid and alpha-ketoglutaric aic. The two enzymes were partially purified and separated from each other by various chromatographies. beta-Alanine:pyruvic acid transaminase and gamma-aminobutyric acid:alpha-ketoglutaric acid transaminase were induced by the addition of beta-alanine and gamma-aminobutyric acid, respectively, to the growth medium. beta-Alanine transaminase showed an optimum pH of 10.0 and optimum temperature of 35 degrees C, and its Km values for beta-alanine and pyruvic acid were both 1.1 mM. gamma-Aminobutyric acid, epsilon-aminocaproic acid, 2-aminoethylphosphonic acid, and propylamine showed about 30-40% of the activity of beta-alanine as amino donors, and oxalacetic acid was as good an amino acceptor as pyruvic acid. The optimum pH and temperature of gamma-aminobutyric acid transaminase were 9.0 and 50 degrees C, respectively, and its Km value for gamma-aminobutyric acid was 2.8 mM, while that for alpha-ketoglutaric acid was 2.3 mM. gamma-Aminobutyric acid and delta-aminovaleric acid were good amino donors but other omega-amino acids were virtually inactive with gamma-aminobutyric acid transaminase; alpha-ketoglutaric acid, and to a lesser extent glyoxylic acid, were active amino acceptors. Sulfhydryl reagents specifically activated gamma-aminobutyric acid transaminase.
D000612:4-Aminobutyrate Transaminase / Q000302:isolation & purification / Q000378:metabolism; D000410:Alanine Transaminase / Q000302:isolation & purification / Q000378:metabolism; D000596:Amino Acids; D001409:Bacillus cereus / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D000637:Transaminases / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D000637:Transaminases; D000612:4-Aminobutyrate Transaminase; D000410:Alanine Transaminase