Human brain monoamine oxidase type B: mechanism of deamination as probed by steady-state methods.
Human brain monoamine oxidase type B: mechanism of deamination as probed by steady-state methods.
复制标题
人脑 B 型单胺氧化酶：稳态方法探讨的脱氨机制。
作者：
L. Pearce;J. Roth
最近，有证据表明[Husain， M., Edmondson， D. E., & Singer， T.P. (1982) Biochemistry 21,595 -600]单胺氧化酶[amine:oxygen oxidoreductase (MAO), EC 1.4.3.4]通过两种不同的动力学途径分别涉及二元或三元络合物的形成，对苯乙胺和苄胺进行脱胺。这些结论主要来自于对从其天然膜上去除的纯化酶进行的停流动力学分析，并在抑制洗涤剂Triton X-100的存在下得出。在这项研究中，d-安非他明和替代底物作为稳态探针，利用天然膜结合酶对人脑MAO B型脱胺动力学进行研究。初始速度研究表明，当胺或氧为不同底物时，安非他明对苯乙胺、色胺和酪胺的抑制呈混合型模式。除苯乙胺（双曲线）外，斜率和截距与安非他明浓度的重绘图在所有情况下都是线性的；从斜率或截距值的线性重绘得到的Ki值具有可比性。相反，安非他明在胺浓度变化时是苯胺脱胺的竞争性抑制剂，在氧浓度变化时是非竞争性抑制剂；斜率和截距重绘均为线性。当苯胺作为备选底物抑制剂时，测定酪胺和色胺脱胺的浓度，无论胺浓度还是氧浓度，都得到混合型抑制模式；所有病例的斜率和截距重绘均为线性。（摘要删节250字）
Recently, evidence has been published which suggests that [Husain, M., Edmondson, D. E., & Singer, T.P. (1982) Biochemistry 21, 595-600] monoamine oxidase [amine:oxygen oxidoreductase (MAO), EC 1.4.3.4] deaminates phenylethylamine and benzylamine via two distinct kinetic pathways which involve either binary or ternary complex formation, respectively. These conclusions were drawn largely from stopped-flow kinetic analysis performed on purified enzyme removed from its native membrane and in the presence of the inhibitory detergent Triton X-100. In this study, d-amphetamine and alternative substrates were used as steady-state probes of the kinetics of deamination by the B form of human brain MAO using native membrane-bound enzyme. Initial velocity studies showed mixed-type patterns for amphetamine inhibition of phenylethylamine, tryptamine, and tyramine when either amine or oxygen was the varied substrate. Slope and intercept vs. amphetamine concentration replots were linear in all cases except for phenylethylamine (hyperbolic); Ki values obtained from linear replots of slope or intercept values were comparable. In contrast, amphetamine was a competitive inhibitor of benzylamine deamination when amine concentration was varied and uncompetitive when oxygen concentration was varied; slope and intercept replots were linear for both. When benzylamine was the alternative substrate inhibitor and tyramine and tryptamine deamination was measured, mixed-type inhibition patterns were obtained when either amine or oxygen concentration was varied; replots of slope and intercept were linear in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)
肝脏单胺氧化酶催化机制的动力学研究。
影响因子：
2.9
作者：
Husain,M;Edmondson,DE;Singer,TP
通讯作者：
Singer,TP