Kinetic studies on the catalytic mechanism of liver monoamine oxidase.
Kinetic studies on the catalytic mechanism of liver monoamine oxidase.
复制标题
肝脏单胺氧化酶催化机制的动力学研究。
DOI：
10.1021/bi00532a028
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发表时间：
1982
期刊：
影响因子：
2.9
通讯作者：
Singer,TP
中科院分区：
文献类型：
--
作者：
Husain,M;Edmondson,DE;Singer,TP
作者：Mazhar Husain，Dale E. Edmondson，** 和托马斯P. Singer* 摘要：采用稳态和准稳态技术研究了牛肝线粒体单胺氧化酶的动力学机制。平行线双倒数图，观察与所有基板测试通过使用传统的或停流监测稳态的方法。在25 ℃下，用任一技术在苄胺和氧的无限浓度下观察到~ 800 min-1的最大速度，表明催化活性不受酶浓度的HP倍数变化的影响。稳态研究比较了[1，2，2]-苄胺和苄胺，得到了6.4-6.7的动力学同位素效应，对苄胺和O2的Km值没有影响。在停流实验中厌氧测定的单胺氧化酶的还原速率给出了k3= 700 min-1的外推值和8.7的kH/kD。未观察到同位素效应对底物结合（Ks）的影响。底物或连二亚硫酸盐还原的单胺氧化酶的再氧化速率
Mazhar Husain, Dale E. Edmondson,** and Thomas P. Singer* abstract: The kinetic mechanism of mitochondrial mono-amine oxidase from beef liver has been investigated by steady-state and pre-steady-state techniques. Parallel line double-reciprocal plots were observed with all substrates tested by using either conventional or stopped-flow-monitored steady-state approaches. A maximal velocity of~ 800 min" 1 at infinite concentrations of benzylamine and oxygen was observed at 25 C with either technique, showing that the catalytic activity is not affected by a HP-fold change in enzyme concentration. Steady-state studies comparing [,-2 2]-benzylamine and benzylamine gave a kinetic isotope effect of 6.4-6.7, with no effect on Km values for benzylamine and 02. The rate of reduction of monoamine oxidase determined anaerobically in stopped-flow experiments gave an extrapolated value of k3= 700 min'1 and a kH/kD of 8.7. No isotope effect was observed on substrate binding (Ks). The rate of reoxidation of substrate-or dithionite-reduced monoamineoxidase