Katayama M, Kobayashi S, Oguchi K, Yasuhara H
Jpn J Pharmacol. 1984 Aug;35(4):425-31. doi: 10.1254/jjp.35.425.
The activities of monoamine oxidase (MAO) in a homogenate and the mitochondrial fraction of monkey (Macaca fascicularis) heart were measured with labelled benzylamine, serotonin (5-HT), tyramine and beta-phenylethylamine (PEA) as substrates. The effects of clorgyline, deprenyl and semicarbazide on MAO were also investigated. Benzylamine deamination was more sensitive to deprenyl than to clorgyline, although it was not completely inhibited by a high concentration of either, and the remaining activity was completely inhibited by pretreatment with semicarbazide. The activities of 5-HT and tyramine were both more sensitive to clorgyline than to deprenyl, and both inhibitors gave single-sigmoidal inhibition curves. Experiments with increasing concentrations of PEA as substrate and clorgyline and deprenyl as inhibitors indicated that at higher concentrations, PEA was a substrate for MAO-A as well as MAO-B in monkey heart. These results suggest that monkey heart mitochondria contain not only MAO-A and MAO-B, but also clorgyline resistant amine oxidase (CRAO). The ratio of MAO-A, MAO-B and CRAO was determined from plots of inhibitions with each substrate. The kinetic constants of MAO in monkey heart were compared with those of MAO in hearts of other animals. The enzymic properties of MAO in monkey heart were discussed on the basis of these results.
以标记的苄胺、5-羟色胺（5-HT）、酪胺和β-苯乙胺（PEA）为底物，测定了恒河猴心脏匀浆和线粒体部分中单胺氧化酶（MAO）的活性。还研究了氯吉兰、司来吉兰和氨基脲对MAO的影响。苄胺脱氨对司来吉兰比对氯吉兰更敏感，尽管高浓度的任何一种都不能完全抑制，而剩余活性可被氨基脲预处理完全抑制。5-HT和酪胺的活性对氯吉兰比对司来吉兰都更敏感，且两种抑制剂均给出单S形抑制曲线。以增加浓度的PEA为底物、氯吉兰和司来吉兰为抑制剂进行的实验表明，在较高浓度下，PEA是恒河猴心脏中MAO-A以及MAO-B的底物。这些结果表明，恒河猴心脏线粒体不仅含有MAO-A和MAO-B，还含有氯吉兰抗性胺氧化酶（CRAO）。根据每种底物的抑制曲线确定MAO-A、MAO-B和CRAO的比例。将恒河猴心脏中MAO的动力学常数与其他动物心脏中MAO的动力学常数进行了比较。基于这些结果讨论了恒河猴心脏中MAO的酶学性质。
