Department of Chemistry, Kwangwoon University, Seoul 139-701, Republic of Korea.
Biochem Biophys Res Commun. 2010 Dec 17;403(3-4):442-6. doi: 10.1016/j.bbrc.2010.11.052. Epub 2010 Nov 19.
Cysteamine (1) was reported many years ago to reversibly inhibit lentil seedling amine oxidase, through the formation of a complex with thioacetaldehyde, the turnover product of 1. Herein, cysteamine (1) and its analogs 2-(methylamino)ethanethiol (3) and 3-aminopropanethiol (6) were found to be reversible inhibitors of bovine plasma amine oxidase (BPAO), but 2-(methylthio)ethylamine (7) was determined to be a weak irreversible inhibitor of BPAO. Based on our results, indicating the necessity of a sulfhydryl-amine for reversible inactivation of BPAO, the failure of inhibited BPAO to recover activity after gel filtration, the first-order kinetics of activity recovery upon dialysis, and 2,4,6-trihydroxyphenylalanine quinine (TPQ) cofactor transformation which indicated from the results of phenylhydrazine titration and substrate protection, we propose a mechanism for the reversible inactivation of BPAO by 1 involving the formation of a cofactor adduct, thiazolidine, between BPAO and 1.
半胱胺（1）多年前被报道可通过与硫代乙醛（1 的转化产物）形成复合物，可逆地抑制菜豆幼苗胺氧化酶。在此，发现半胱胺（1）及其类似物 2-（甲氨基）乙硫醇（3）和 3-氨基丙硫醇（6）是牛血浆胺氧化酶（BPAO）的可逆抑制剂，但 2-（甲硫基）乙胺（7）被确定为 BPAO 的弱不可逆抑制剂。基于我们的结果，表明了对于 BPAO 的可逆失活，巯基-胺的必要性，被抑制的 BPAO 在凝胶过滤后无法恢复活性，在透析过程中活性恢复的一级动力学，以及 2,4,6-三羟基苯丙氨酸奎宁（TPQ）辅因子转化，这些结果表明苯肼滴定和底物保护实验结果，我们提出了一个 BPAO 被 1 可逆失活的机制，涉及 BPAO 和 1 之间形成辅因子加合物噻唑烷。
