Ricoux R, Boucher J L, Mansuy D, Mahy J P
Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601 CNRS, Université Paris V, 45 rue des Saints-Pères, 75270, Paris cedex 06, France.
Biochem Biophys Res Commun. 2000 Nov 11;278(1):217-23. doi: 10.1006/bbrc.2000.3785.
Microperoxidase 8 (MP8) is a heme octapeptide, obtained by enzymatic hydrolysis of heart cytochrome c, in which a histidine is axially coordinated to the heme iron, and acts as its fifth ligand. It exhibits two kinds of activities: a peroxidase-like activity and a cytochrome P450-like activity. We here show that MP8 is not only able to oxidize various aliphatic and aromatic hydroxylamines with the formation of MP8-Fe(II)-nitrosoalkane or -arene complexes absorbing around 414 nm, but also that these complexes can be obtained by reduction of nitroalkanes. This is the first example of fully characterized iron(II)-metabolite complexes of MP8. Such complexes constitute good models for those obtained upon oxidation of amphetamine or macrolids by cytochromes P450. In addition, this is a new catalytic activity of MP8, which validates the use of this mini-enzyme as a convenient model for hemoproteins of interest in toxicology and pharmacology such as cytochromes P450 and peroxidases.
微过氧化物酶8（MP8）是一种血红素八肽，通过心脏细胞色素c的酶促水解获得，其中一个组氨酸轴向配位至血红素铁，并作为其第五个配体。它表现出两种活性：类似过氧化物酶的活性和类似细胞色素P450的活性。我们在此表明，MP8不仅能够氧化各种脂肪族和芳香族羟胺，形成在414nm左右有吸收的MP8-Fe（II）-亚硝基烷烃或 - 芳烃配合物，而且这些配合物可以通过硝基烷烃的还原得到。这是MP8完全表征的铁（II）-代谢物配合物的第一个例子。此类配合物是细胞色素P450氧化苯丙胺或大环内酯类化合物时所得到的配合物的良好模型。此外，这是MP8的一种新的催化活性，这证实了将这种微型酶用作毒理学和药理学中感兴趣的血红素蛋白（如细胞色素P450和过氧化物酶）的便捷模型的用途。
