Alanine dehydrogenase of the β-lactam antibiotic producerStreptomyces clavuligerus

✍ Scribed by Yair Aharonowitz; Cornelius G. Friedrich

• Book ID: 104759202
• Publisher: Springer
• Year: 1980
• Tongue: English
• Weight: 937 KB
• Volume: 125
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00403210

✦ Synopsis

L-Alanine dehydrogenase was found in extracts of the antibiotic producer Streptornyces clavutigerus. The enzyme was induced by ammonia, and the leveI of induction was dependend on the extracellular concentratiom L-Alanine was the only amino acid able to induce atanine dehydrogenase. The enzyme was characterized from a 38-fold purified preparation. Pyruvate (K m = 1.1 raM), ammonia (K m = 20 mM) and NADH (K,, = 0.14 raM) were required for the reductive amination, and L-alanine (K,~ = 9.1 mM) and NAD (K,, = 0.5 raM) for the oxidative deaminating reaction. The aminating reaction was inhibited by alanine, serine and NADPH. Alanine inhibited uncompetitively with respect to NADH (K~ = 1.6 raM) and noncompetitively with respect to ammonia (K~ = 2.0 mM) and pyruvate (K~ = 3.0 mM). In the aminating reaction 3-hydroxypyruvate, glyoxylate and 2-oxobutyrate could partially (6 ~-7 ~/~) substitute pyruvate. Atanine dehydrogenase from & clavulige~us differed with respect to its molecular weight (92000) and its kinetic properties from those described for other microorganisms.