Severina I S, Klimova G I, Nersisian A A
Biokhimiia. 1981 Nov;46(11):2043-55.
A comparative study of the inhibitory effect of clorgyline and deprenyl on serotonin, beta-phenylethylamine and tyramine deamination by intact mitochondria as well as by solubilized with methylethylketone and partially purified monoamine oxidase (MAO) from rat liver was carried out. The effect of 4-ethylpyridine on this process was investigated. After solubilization of MAO by methylethylketone 7% of mitochondrial activity passes into solution and the rate of deamination of serotonin, tyramine and beta-phenylethylamine by soluble MAO preparation is selectively decreased. The corresponding residual activities are equal to 29, 63, 86 and 92%. The inhibitory effect of clorgyline on serotonin deamination by soluble MAO preparations is considerably lower than that by mitochondrial suspensions at the concentrations of the inhibitor from 1 x 10(-4) to 1 x 10(-7) M, while the inhibitory action of clorgyline on tyramine deamination after MAO solubilization by methylethylketone is increased at 10(-4) and 10(-5) M, but decreased insignificantly at 10(-6) and 10(-7) M. When solubilized MAO preparations are used, 4-ethylpyridine introduced into the sample before or after preincubation of the enzyme with clorgyline (30 min, 23 degrees) eliminates the inhibitory action of the latter on serotonin and tyramine deamination, thus suggesting the reversibility of the inhibitory effect of clorgyline. In similar experiments with mitochondrial suspensions the inhibition by clorgyline of deamination of these amines is irreversible. Similar experiments on mitochondrial suspensions showed that clorgyline irreversibly inhibits the deamination of these amines. The rate of inhibition by deprenyl of beta-phenylethylamine oxidation due to MAO solubilization by methylethylketone is not changed. 4-Ethylpyridine added to the samples before or after preincubation of deprenyl with the enzyme (30 min, 23 degrees) abolishes the inhibiting effect of the former both in soluble MOA and in mitochondrial suspensions. This suggests that under the given experimental conditions the inhibiting effect of deprenyl is reversible. Possible nature of MAO forms A and B is discussed.
进行了一项比较研究，考察了氯吉兰和司来吉兰对完整线粒体以及用甲乙酮溶解并部分纯化的大鼠肝脏单胺氧化酶（MAO）脱氨作用的抑制效果，该脱氨作用涉及血清素、β-苯乙胺和酪胺。研究了4-乙基吡啶对这一过程的影响。用甲乙酮溶解MAO后，7%的线粒体活性进入溶液，可溶性MAO制剂对血清素、酪胺和β-苯乙胺的脱氨速率选择性降低。相应的残余活性分别为29%、63%、86%和92%。在抑制剂浓度为1×10⁻⁴至1×10⁻⁷ M时，氯吉兰对可溶性MAO制剂脱氨血清素的抑制作用远低于对线粒体悬浮液的抑制作用，而在用甲乙酮溶解MAO后，氯吉兰对酪胺脱氨的抑制作用在10⁻⁴和10⁻⁵ M时增强，但在10⁻⁶和10⁻⁷ M时略有降低。当使用可溶性MAO制剂时，在酶与氯吉兰预孵育（30分钟，23℃）之前或之后加入样品中的4-乙基吡啶消除了氯吉兰对血清素和酪胺脱氨的抑制作用，这表明氯吉兰的抑制作用是可逆的。在对线粒体悬浮液进行的类似实验中，氯吉兰对这些胺类脱氨的抑制作用是不可逆的。对线粒体悬浮液进行的类似实验表明，氯吉兰不可逆地抑制这些胺类的脱氨。由于用甲乙酮溶解MAO，司来吉兰对β-苯乙胺氧化的抑制速率没有变化。在司来吉兰与酶预孵育（30分钟，23℃）之前或之后加入样品中的4-乙基吡啶消除了其在可溶性MAO和线粒体悬浮液中的抑制作用。这表明在给定的实验条件下，司来吉兰的抑制作用是可逆的。讨论了MAO A和B型的可能性质。
