Amphitrite ornata dehaloperoxidase:: enhanced activity for the catalytically active globin using MCPBA
Amphitrite ornata dehaloperoxidase:: enhanced activity for the catalytically active globin using MCPBA
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DOI：
10.1016/j.bbrc.2004.09.174
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发表时间：
2004-11-26
影响因子：
3.1
通讯作者：
Dawson, JH
中科院分区：
文献类型：
--
作者：
Osborne, RL;Taylor, LO;Dawson, JH
脱卤过氧化物酶（DHP）是唯一的含血红素，过氧化氢依赖的珠蛋白，能够氧化脱卤，产生相应的醌。为了确定这种酶活性是DHP固有的，我们克隆并在大肠杆菌中表达了这种酶。我们还发现另一种氧原子供体，间氯过苯甲酸，其活性明显高于过氧化氢。在最佳转化条件下（大量过氧化物/过酸过量），在初始活性爆发后，DHP似乎被困在非催化状态（可能是化合物II），无法完全将所有卤代酚转化为产物。然而，完全底物转化可以在更生理的条件下实现，涉及更小的过量氧原子供体。平行研究已分别使用辣根过氧化物酶和肌红蛋白来校准DHP与典型过氧化物酶和球蛋白蛋白的活性。(C) 2004爱思唯尔公司版权所有。
Dehaloperoxidase (DHP) from Amphitrite ornata is the only heme-containing, hydrogen peroxide-dependent globin capable of oxidatively dehalogenating halophenols to yield the corresponding quinones. To ascertain that this enzymatic activity is intrinsic to DHP, we have cloned and expressed the enzyme in Escherichia coli. We also find that an alternate oxygen atom donor, meta-chloroperbenzoic acid, gives appreciably higher activity than hydrogen peroxide. Under optimal turnover conditions (large peroxide/peracid excess), after an initial burst of activity, DHP appears to become trapped in a non-catalytic state (possibly Compound II) and is unable to fully convert all halophenol to product. However, full substrate conversion can be achieved under more physiological conditions involving a much smaller excess of oxygen atom donor. Parallel studies have been carried out using horseradish peroxidase and myoglobin to calibrate the activity of DHP versus typical peroxidase and globin proteins, respectively. (C) 2004 Elsevier Inc. All rights reserved.