Akhrem A A, Eremin A N, Usanov S A, Metelitsa D I
Biokhimiia. 1978 Sep;43(9):1578-85.
Naphthalene and aniline oxidation by intact and induced enzyme systems of rat liver microsomes, NADPH and O2 has been studied in a broad temperature range. The oxidation of the same substrates has also been studied in the systems "microsomes--cumene hydroperoxide" and "purified cytochrome P-450--cumene hydroperoxide". The temperature curves of catalytic constants for type I substrate (naphthalene-oxidation) in the system with cofactors is characterized by break on Arrenius dependence near 18--24 degrees C and explained by phase transitions of microsomal membrane lipids. The temperature curves of catalytic constants for type II substrate (aniline-oxidation) in all studied systems do not break on Arrenius plots. Catalytic oxidation contants of both substrates in systems "microsomes--hydroperoxide" and "cytochrome P-450--hydroperoxide" are characterized by constant activation energies in broad temperature range. The results obtained are discussed from the point of view of the effect of phospholipids phase transitions in microsomal membrane on a rate limiting step.
在很宽的温度范围内，研究了大鼠肝脏微粒体完整及诱导酶系统、NADPH和O₂对萘和苯胺的氧化作用。还在“微粒体 - 氢过氧化异丙苯”和“纯化细胞色素P - 450 - 氢过氧化异丙苯”系统中研究了相同底物的氧化作用。在有辅因子的系统中，I型底物（萘氧化）催化常数的温度曲线在18 - 24℃附近阿累尼乌斯关系上有断点，这可由微粒体膜脂质的相变来解释。在所有研究系统中，II型底物（苯胺氧化）催化常数的温度曲线在阿累尼乌斯图上没有断点。“微粒体 - 氢过氧化物”和“细胞色素P - 450 - 氢过氧化物”系统中两种底物的催化氧化常数在很宽温度范围内具有恒定的活化能。从微粒体膜中磷脂相变对限速步骤的影响角度对所得结果进行了讨论。
