Aharonowitz Y, Friedrich C G
Arch Microbiol. 1980 Mar;125(1-2):137-42. doi: 10.1007/BF00403210.
L-Alanine dehydrogenase was found in extracts of the antibiotic producer Streptomyces clavuligerus. The enzyme was induced by ammonia, and the level of induction was dependent on the extracellular concentraction. L-Alanine was the only amino acid able to induce alanine dehydrogenase. The enzyme was characterized from a 38-fold purified preparation. Pyruvate (Km = 1.1 mM), ammonia (Km = 20 mM) and NADH (Km = 0.14 mM) were required for the reductive amination, and L-alanine (Km = 9.1 mM) and NAD (Km = 0.5 mM) for the oxidative deaminating reaction. The aminating reaction was inhibited by alanine, serine and NADPH. Alanine inhibited uncompetitively with respect to NADH (Ki = 1.6 mM) and noncompetitively with respect to ammonia (Ki = 2.0 mM) and pyruvate (Ki = 3.0 mM). In the aminating reaction 3-hydroxypyruvate, glyoxylate and 2-oxobutyrate could partially (6--7%) substitute pyruvate. Alanine dehydrogenase from S. clavuligerus differed with respect to its molecular weight (92000) and its kinetic properties from those described for other microorganisms.
在抗生素产生菌棒状链霉菌的提取物中发现了L-丙氨酸脱氢酶。该酶由氨诱导，诱导水平取决于细胞外浓度。L-丙氨酸是唯一能够诱导丙氨酸脱氢酶的氨基酸。该酶是从38倍纯化的制剂中鉴定出来的。还原胺化反应需要丙酮酸（Km = 1.1 mM）、氨（Km = 20 mM）和NADH（Km = 0.14 mM），氧化脱氨反应需要L-丙氨酸（Km = 9.1 mM）和NAD（Km = 0.5 mM）。胺化反应受到丙氨酸、丝氨酸和NADPH的抑制。丙氨酸对NADH的抑制作用为非竞争性（Ki = 1.6 mM），对氨（Ki = 2.0 mM）和丙酮酸（Ki = 3.0 mM）的抑制作用为非竞争性。在胺化反应中，3-羟基丙酮酸、乙醛酸和2-氧代丁酸可以部分（6-7%）替代丙酮酸。棒状链霉菌的丙氨酸脱氢酶在分子量（92000）及其动力学性质方面与其他微生物中描述的不同。
