[单胺氧化酶（XXXVI）。犬血清中苄胺氧化酶的特性]

[Monoamine oxidase (XXXVI). Characteristics of benzylamine oxidase in the dog serum].

作者信息

Fukushima T

出版信息

Nihon Yakurigaku Zasshi. 1975 Jul;71(5):457-62.

PMID:280

Abstract

Enzymic properties of monoamine oxidase (MAO) in dog serum were studied and the following results were obtained. Some of enzymic properties of MAO in dog serum differed from that of mitochondrial MAO. When dog serum was fractionated by ammonium sulfate, proteins were concentrated in two fractions, such as 25 approximately 33% and 67 approximately 80% of saturated ammonium sulfate fraction, while MAO activity was concentrated in 40 approximately 50% of saturated ammonium sulfate fraction. The reaction rate of MAO in dog serum was found to be proportional to enzyme concentration. The optimum pH of MAO in dog serum was 7.0 which differed from that of MAO in rabbit serum (pH 8.0). Tris-HCl buffer strongly inhibited MAO activity in dog serum. When benzylamine was used as substrate, the highest activity was obtained compared with the other substrate used. The activities with butylamine, amylamine, beta-phenylethylamine and tyramine showed about 30% while tryptamine and serotonin showed 3 approximately 10% compared to that with benzymlamine as substrate. The value of pI50 of catron was about 3 X 10(-6) M and that of harmaline was about 3 X 10(-5) M, but pargyline did not inhibit MAO activity in dog serum at the concentration of 1 X 10(-4) M.

摘要

对犬血清中单胺氧化酶（MAO）的酶学性质进行了研究，获得了以下结果。犬血清中MAO的一些酶学性质与线粒体MAO不同。当用硫酸铵对犬血清进行分级分离时，蛋白质集中在两个级分中，如25%至33%饱和度硫酸铵级分和67%至80%饱和度硫酸铵级分，而MAO活性集中在40%至50%饱和度硫酸铵级分中。发现犬血清中MAO的反应速率与酶浓度成正比。犬血清中MAO的最适pH为7.0，这与兔血清中MAO的最适pH（8.0）不同。Tris-HCl缓冲液强烈抑制犬血清中的MAO活性。当使用苄胺作为底物时，与使用的其他底物相比，获得了最高活性。与以苄胺为底物相比，丁胺、戊胺、β-苯乙胺和酪胺的活性约为30%，而色胺和5-羟色胺的活性约为3%至10%。卡卓隆的pI50值约为3×10⁻⁶ M，哈马灵的pI50值约为3×10⁻⁵ M，但在1×10⁻⁴ M浓度下，帕吉林不抑制犬血清中的MAO活性。