中-α,ε-二氨基庚二酸 D-脱氢酶：分布及反应产物
Meso-alpha,epsilon-diaminopimelate D-dehydrogenase: distribution and the reaction product.
作者信息
Misono H, Togawa H, Yamamoto T, Soda K
出版信息
J Bacteriol. 1979 Jan;137(1):22-7. doi: 10.1128/jb.137.1.22-27.1979.
A high activity of meso-alpha-epsilon-diaminopimelate dehydrogenase was found in extracts of Bacillus sphaericus, Brevibacterium sp., Corynebacterium glutamicum, and Proteus vulgaris among bacteria tested. B. sphaericus IFO 3525, in which the enzyme is most abundant, was chosen to study the enzyme reaction. The enzyme was not induced by the addition of meso-alpha-epsilon-diaminopimelate to the growth medium. The reaction product was isolated and identified as alpha-amino-epsilon-ketopimelate by a comparison of the properties of its 2,4-dinitrophenylhydrazone with those of an authentic sample in silica gel thin-layer chromatography, absorption, infrared and proton nuclear magnetic resonance spectrometry, and elemental analyses. The alpha-amino-epsilon-ketopimelate formed enzymatically was decarboxylated by H2O2 to yield L-alpha-aminoadipate. This suggests that the amino group with D-configuration in the substrate is oxidatively deaminated; the enzyme is a D-amino acid dehydrogenase. L-alpha-Amino-epsilon-ketopimelate undergoes spontaneous dehydration to the cyclic delta1-piperideine-2,6-dicarboxylate. The enzyme reaction is reversible, and meso-alpha-epsilon-diaminopimelate was formed in the reductive amination of L-alpha-epsilon-ketopimelate.
在所测试的细菌中，球形芽孢杆菌、短杆菌属、谷氨酸棒杆菌和普通变形杆菌的提取物中发现了高活性的内消旋-α,ε-二氨基庚二酸脱氢酶。选择酶含量最丰富的球形芽孢杆菌IFO 3525来研究酶反应。向生长培养基中添加内消旋-α,ε-二氨基庚二酸不会诱导该酶的产生。通过比较其2,4-二硝基苯腙与硅胶薄层层析中真实样品的性质、吸收光谱、红外光谱和质子核磁共振光谱以及元素分析，分离并鉴定反应产物为α-氨基-ε-酮基庚二酸。酶促形成的α-氨基-ε-酮基庚二酸被过氧化氢脱羧生成L-α-氨基己二酸。这表明底物中具有D-构型的氨基被氧化脱氨；该酶是一种D-氨基酸脱氢酶。L-α-氨基-ε-酮基庚二酸会自发脱水生成环状δ1-哌啶-2,6-二羧酸。该酶反应是可逆的，在L-α,ε-酮基庚二酸的还原胺化反应中形成了内消旋-α,ε-二氨基庚二酸。
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