Standard reduction potentials of all couples of the peroxidase cycle of lactoperoxidase
Standard reduction potentials of all couples of the peroxidase cycle of lactoperoxidase
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DOI：
10.1016/j.jinorgbio.2005.02.021
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发表时间：
2005-05-01
影响因子：
3.9
通讯作者：
Obinger, C
中科院分区：
文献类型：
--
作者：
Furtmüller, PG;Arnhold, J;Obinger, C
乳过氧化物酶(LPO)广泛存在于乳汁、泪液和唾液等粘膜表面和外分泌物中，在抗菌防御中具有重要的生理意义。它的主要生理作用是将过氧化氢和硫氰酸盐转化为次硫氰酸盐。在本研究中，用多次混合停流光谱测定了参与LPO卤化和过氧化物酶循环的所有氧化还原对的标准还原电位。化合物I/天然LPO，化合物I/天然LPO，化合物II/天然LPO的标准还原电位分别为(1.09+/-0.01)V，(1.14+/-0.02)V，和(1.04+/-0.02)V，在pH 7和25℃。因此，首次对这些重要的乳过氧化物的热力学参数进行了全面的描述，从而更好地理解了LPO和其他哺乳动物血红素过氧化物酶超家族成员氧化两个和一个电子供体的本质差异。(C)2005 Elsevier Inc.保留所有权利。
Lactoperoxidase (LPO) is found in mucosal surfaces and exocrine secretions including milk, tears and saliva and has physiological significance in antimicrobial defense. Its predominant physiological role is to convert hydrogen peroxide and thiocyanate in hypothiocyanite. In this study, the standard reduction potentials of all redox couples involved in the halogenation and peroxidase cycle of LPO have been determined by multi-mixing stopped-flow spectroscopy. The standard reduction potentials of the redox couples compound I/native LPO, compound I/compound II of LPO, and compound II/native LPO are (1.09 +/- 0.01) V, (1.14 +/- 0.02) V, and (1.04 +/- 0.02) V, respectively, at pH 7 and 25 degrees C. Thus, for the first time, a full description of these important thermodynamic parameters of lactoperoxidase has been performed, allowing a better understanding in the substantial differences in the oxidation of two- and one-electron donors by LPO and other members of the mammalian heme peroxidase superfamily. (c) 2005 Elsevier Inc. All rights reserved.