Cofactor-Dependent Amine Oxidations

描述（由申请人提供）：含铜胺氧化酶（CAO）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在参与生长、细胞分裂、分化和应激反应的生物胺代谢中起重要作用，其中代谢在某些情况下具有细胞毒性后果。所有的CAO利用醌辅因子从活性位点酪氨酸残基翻译后衍生介导的transaminative转化伯胺醛。在过去的资助期内，使用辅因子模型的研究激发了新型酶激活抑制机制的发现。这些研究，沿着其他传统失活策略的发展，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区分黄素和醌依赖性酶，而且区分一系列具有不同底物结构偏好的CAO。自上次更新以来，人类CAO的两大类的遗传基础已被揭示：（i）三羟基苯丙氨酸醌（TPQ）依赖性AOC 1类（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，以及（ii）除经典LOX外的四种赖氨酰氧化酶样（LOXL）蛋白。在下一个资助期内，将更加关注改善人类酶的抑制剂选择性，特别是肾脏/胎盘二胺氧化酶、可溶性和组织结合氨基脲敏感性单胺氧化酶和赖氨酰氧化酶。新的目标包括开发灵敏的荧光检测方法，用于检测和定位哺乳动物CAO，探索新的抑制剂选择性和前药结构，使用X射线晶体学信息（通过合作）用于改进由分子建模构建的底物和抑制剂结合模型，以及使用光谱学和质谱法来确定不可逆抑制剂作用的结构基础。此外，还将完成对（TPQ）辅因子生物发生性质的研究。 本研究与公共卫生的相关性 铜胺氧化酶已成为重要的药物靶标，因为它们在炎症、免疫调节、关节炎和动脉粥样硬化中的纤维化以及糖尿病和心血管疾病的晚期并发症方面的关键生理作用的认识正在出现。因此，重要的是要了解这些酶的功能，无论是从机理的角度来看，并在底物识别的结构基础和抑制剂的作用，可以在最终的药物开发中发挥作用。

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.