Beaune P
INSERM U 75, CHU, Necker-Enfants-Malades, Université René Descartes, Paris.
Therapie. 1993 Nov-Dec;48(6):521-6.
Cytochromes P450 (P450) are hemoproteins which catalyze essentially monooxygenation reactions. These enzymes may metabolize either endogenous compounds such as steroids, or exogenous compounds. This review will concentrate on P450 metabolizing xenobiotics. They are found mainly in endoplasmic reticulum of hepatocytes. Purification and cloning of the different isoforms allowed to set up an international nomenclature based on sequences similarities between these P450. Ten families are known in mammals and 4 (CYP 1 to 4) metabolize xenobiotics. Each family may include several subfamilies (A, B, ...). Numerous factors cause variations in the expression of these P450: genetic, environmental, physiopathologic. Several genetic polymorphism have been described, P450, 2D6, 2C and may be 1A2 and 2E1. Some P450 (3A, 1A, 2E, ...) are inducible by compounds such as phenobarbital, rifampicin, aromatic hydrocarbon, ethanol, or omeprazole. Finally, P450 expression and inducibility vary depending on tissues. It is now possible to determine which isoform(s) is (are) responsible of the production of a metabolite. Specific tests are now available to evaluate the level of P450 in vivo in man (1A, 3A, 2D6, 2C).
细胞色素P450（P450）是一类血红素蛋白，主要催化单加氧反应。这些酶可代谢内源性化合物，如类固醇，也可代谢外源性化合物。本综述将聚焦于代谢外源性物质的P450。它们主要存在于肝细胞的内质网中。不同同工型的纯化和克隆使得基于这些P450之间的序列相似性建立了国际命名法。哺乳动物中已知有十个家族，其中4个家族（CYP 1至4）代谢外源性物质。每个家族可能包括几个亚家族（A、B等）。许多因素会导致这些P450表达的变化：遗传、环境、生理病理因素。已经描述了几种基因多态性，如P450、2D6、2C，可能还有1A2和2E1。一些P450（3A、1A、2E等）可被苯巴比妥、利福平、芳香烃、乙醇或奥美拉唑等化合物诱导。最后，P450的表达和诱导性因组织而异。现在有可能确定是哪种同工型负责代谢物的产生。现在有特定的检测方法可用于评估人体体内P450的水平（1A、3A、2D6、2C）。
