Metal ions in enzymes using ammonia or amides.
Metal ions in enzymes using ammonia or amides.
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使用氨或酰胺的酶中的金属离子。
DOI：
10.1126/science.769157
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发表时间：
1976
期刊：
影响因子：
56.9
通讯作者：
B. Zerner
中科院分区：
文献类型：
--
作者：
N. Dixon;C. Gazzola;R. Blakeley;B. Zerner
为了了解镍在菜豆尿素酶中的作用(1)，我们转向了在氨的利用、生产或转移中起重要作用的各种其他酶。我们发现了一些酶，包括L-组氨酸和L-苯丙氨酸氨解酶，以及一些在氨基转移酶反应中利用谷氨酰胺或氨的酶，所有这些都证明了尚未报道的过渡金属离子参与了它们的作用机制。我们支持这样的观点，即金属酶的催化可能反映了作为Lewis酸的金属离子本身的化学，而且可能过于强调了酶-金属离子结合的假定的特殊特征(如菌株)。在此背景下，我们讨论了羧基肽酶A催化特定底物水解的机理，并回到尿素酶中来研究镍在其作用机制中的作用。
In an attempt to understand the role of nickel in jack bean urease (1), we turned to a variety of other enzymes important in the utilization, production, or transfer of ammonia. We found several, including the L-histidine and L-phenylalanine ammonialyases and some enzymes that utilize glutamine or ammonia in amidotransferase reactions, all of which show evidence for the involvement of as yet unreported transition metal ions in their mechanism of action. We support the view that catalysis by metalloenzymes may be a reflection of the chemistry of the metal ion itself as a Lewis acid, and that perhaps too much emphasis has been placed on supposed special characteristics (such as strains, "entasis") of the enzyme-metal ion association. In this context, we have discussed the mechanism of catalysis of hydrolysis of specific substrates by carboxypeptidase A, and have returned to urease to examine the role of nickel in its mechanism of action.