Cofactor-Dependent Amine Oxidations

描述（由申请人提供）：含铜胺氧化酶（CAOs）是所有生物体中普遍存在的一类酶。在植物和哺乳动物中，cao在代谢与生长、细胞分裂、分化和应激反应有关的生物胺中发挥重要作用，在某些情况下代谢具有细胞毒性后果。所有cao都利用从活性位点酪氨酸残基翻译后衍生的醌辅助因子来介导伯胺到醛的转胺转化。在过去的资助期内，使用辅因子模型的研究激发了发现新型酶激活的抑制机制。这些研究，以及其他传统的失活策略的发展，已经产生了非常有希望的抑制剂选择性程度。所实现的选择性不仅是区分黄素和醌依赖的酶，而且还区分一系列具有不同底物结构偏好的CAOs。自上次更新以来，两类人类CAOs的遗传基础已被揭示：(i)三羟基苯基丙氨酸醌（TPQ）依赖类AOC 1（人肾二胺氧化酶），AOC 2和AOC 3，后者与人血管粘附蛋白-1 （HVAP-1）一致；（ii）除了经典LOX外，还有四种赖氨酸氧化酶样（LOXL）蛋白。在下一个资助期，将增加对精炼人类酶抑制剂选择性的关注，特别是肾/胎盘二胺氧化酶、可溶性和组织结合氨基脲敏感单胺氧化酶和赖氨酸氧化酶。新的目标包括开发用于检测和定位哺乳动物CAOs的灵敏荧光测定法，探索新的抑制剂选择性和前药结构，利用x射线晶体学信息（通过合作）改进通过分子建模构建的底物和抑制剂结合模型，以及使用光谱和质谱法确定不可逆抑制剂作用的结构基础。对（TPQ）辅因子的生物发生性质的研究也将进一步完成。

DESCRIPTION (provided by applicant): The copper-containing amine oxidases (CAOs) comprise a ubiquitous class of enzymes in all living organisms. In plants and mammals, CAOs play important roles in metabolizing biogenic amines involved in growth, cell division, differentiation, and the stress response, where metabolism in some cases has cytotoxic consequences. All CAOs utilize a quinone cofactor derived postranslationally from an active-site tyrosine residue to mediate a transaminative conversion of primary amines to aldehydes. Studies using cofactor models in the past grant periods have inspired the discovery of new types of enzyme-activated mechanisms of inhibition. These studies, along with development of other traditional inactivation strategies, have resulted in highly promising degrees of inhibitor selectivity. The selectivity being achieved is discriminating not only between the flavin- and quinone-dependent enzymes, but also among a range of CAOs that have different substrate-structure preferences. Since the time of the last renewal, the genetic basis of the two general classes of human CAOs has been revealed: (i) the trihydroxyphenylalanine quinone (TPQ)-dependent class AOC 1 (the human kidney diamine oxidase), AOC 2, and AOC 3, the latter coincidental with the human vascular adhesion protein-1 (HVAP-1), and (ii) four lysyl oxidase-like (LOXL) proteins in addition to classical LOX. In the next grant period, there will be increased focus on refining inhibitor selectivity for the human enzymes, particularly the kidney/placental diamine oxidase, the soluble and tissue-bound semicarbazide- sensitive monoamine oxidases, and lysyl oxidase. The new aims include the development of sensitive fluorometric assays for detecting and localizing mammalian CAOs, an exploration of new inhibitor selectivity and prodrug constructs, the use of x-ray crystallographic information (through collaboration) for refinement of substrate and inhibitor binding models constructed by molecular modeling, and the use of spectroscopy and mass spectrometry to identify the structural basis of irreversible inhibitor action. Studies on the nature of biogenesis of the (TPQ) cofactor will additionally be completed. RELEVANCE OF THIS RESEARCH TO PUBLIC HEALTH The copper amine oxidases have become important pharmaceutical targets on account of the emerging recognition of their key physiological roles in aspects of inflammation, immune modulation, fibrosis in arthritis and atherosclerosis, and in late-stage complications of diabetes and cardiovascular disease. It is thus important to understand the functioning of these enzymes, both from a mechanistic view and in terms of the structural basis of substrate recognition and the action of inhibitors that can serve a leads in eventual drug development.