Deamination of serine. II. D-Serine dehydrase, a vitamin B6 enzyme from Escherichia coli.
Deamination of serine. II. D-Serine dehydrase, a vitamin B6 enzyme from Escherichia coli.
复制标题
丝氨酸的脱氨基作用。
DOI：
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发表时间：
1952
影响因子：
4.8
通讯作者：
E. Snell
中科院分区：
文献类型：
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作者：
D. Metzler;E. Snell
吡哆醛和某些金属盐在100 "时催化丝氨酸和半胱氨酸的非酶解脱胺反应(2)。这一发现表明磷酸吡哆醛可能参与了这些氨基酸的酶解脱胺作用。维生素B已经被证实与大鼠肝脏对半胱氨酸的脱硫作用(3)以及细菌对半胱氨酸和同型半胱氨酸的脱硫作用(4)有关。半胱氨酸脱氢酶和丝氨酸脱氢酶有几个相似之处（5,6）。这些发现支持了维生素Be可能参与丝氨酸脱水的假设，尽管最近有报道称，5-磷酸腺苷和谷胱甘肽是Escherichiu c&(7)中唯一可证明的丝氨酸和苏氨酸脱氨酶（脱氨酶）的辅助因子。从大肠杆菌的细胞中制备需要n-丝氨酸脱氢酶的无细胞形式的吡哆醛磷酸（PLP）如下所述。这种酶很容易从Wood和Gunsalus(7)的丝氨酸脱水酶中分离出来，它似乎是一种l -丝氨酸脱水酶。
Non-enzymatic deamination of serine and cysteine is catalyzed by pyridoxal and certain metal salts at 100” (2). This finding suggested that pyridoxal phosphate might be involved in the enzymatic deamination of these amino acids. Vitamin B, has already been implicated in the desulfhydration of cysteine by rat liver (3) and of cysteine and homocysteine by bacteria (4). Several similarities of cysteine desulfhydrase and of serine dehydrase have been reported (5, 6). These findings supported the supposition that vitamin Be might be involved in serine dehydration, in spite of the recent report that adenosine-5-phosphate and glutathione are the only demonstrable cofactors of serine and threonine dehydrases (deaminases) from Escherichiu c& (7). The preparation in cell-free form of a pyridoxal phosphate (PLP) requiring n-serine dehydrase from cells of E. coli is described below. This enzyme is readily separated from the serine dehydrase of Wood and Gunsalus (7), which appears to be an L-serine dehydrase.