THE KINETIC MECHANISM OF XANTHINE DEHYDROGENASE AND RELATED ENZYMES
THE KINETIC MECHANISM OF XANTHINE DEHYDROGENASE AND RELATED ENZYMES
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DOI：
10.1111/j.1432-1033.1980.tb04476.x
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
RAJAGOPALAN, KV
中科院分区：
文献类型：
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作者：
COUGHLAN, MP;RAJAGOPALAN, KV
黄嘌呤脱氢酶（来自鸡肝）和相关酶含有多组分内部电子转移链。该链的拓扑结构使得底物的氧化和电子受体的还原发生在通过分子内电子转移进行通信的单独的非重叠位点。这些酶的稳态动力学行为理想地适合于2-位点乒乓机制，在2个位点随机添加底物和产物。这些酶的形式机制在此呈现为由稳态段连接的快速平衡随机段的混合物，即，一种快速平衡随机（2-位点）混合乒乓机制。这样的机制可能是在各种含有多个氧化还原活性辅基的氧化酶中起作用。
Xanthine dehydrogenase [from chicken liver] and related enzymes contain multicomponent internal electron transfer chains. The topographical arrangement of this chain is such that the oxidation of substrate and the reduction of the electron acceptor occur at separate non-overlapping sites that communicate by intramolecular electron transfer. The steady-state kinetic behavior of these enzymes is ideally suited to a 2-site ping-pong mechanism, with random addition of substrates and products at the 2 sites. The formal mechanism of these enzymes is presented here as a mixture of rapid equilibrium random segments connected by a steady-state segment, i.e., a rapid-equilibrium random (2-site) hybrid ping-pong mechanism. Such a mechanism is likely to be operative in a variety of oxidative enzymes containing multiple redox-active prosthetic groups.