STRUCTURE/ PHARMACOLOGY OF KING COBRA DIPEPTIDYL PEPTIDASE IV & COTTONMOUTH VENOM

眼镜王蛇二肽基肽酶 IV 的结构/药理学

• 批准号: 7547686
• 负责人: STEVEN D AIRD
• 金额: $ 10.83万
• 依托单位: NORFOLK STATE UNIVERSITY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7547686
• 关键词: enzyme activity; minority institution research support; protein structure function; reptile poison; serine proteinases

This proposal comprises two subproposals that use similar methods. 1. Mammalian dipeptidyl peptidase IV (DPP IV) is a highly glycosylated serine protease, that releases N-terminal dipeptides from oligopeptides. It is both an integral membrane protein (CD26) and a plasma protein, the physiological role of which is unknown (Hosono et at., 1999). Among its diverse physiological roles, DPP IV removes X-Pro, His-Ala or tyr-Ala dipeptides from the N-termini of hormones such as neuropeptide Y and substance P. It was discovered in snake venoms by Jorge da Silva and Aird (2000). DPP IVs role in venom may be to prevent a hypertensive response on the part of the envenomated prey by inactivating vasoconstrictive peptidyl hormones (Aird, 2002). It may also contribute to the persistent hypotension seen in human envenomation and to inflammation. The present study should shed light on the role of human soluble DPP IV. 2. Snake venom enzymes that cleave phosphate esters were first discovered when venom phosphodiesterase (PDE) was reported by Gulland and Jackson (1938). Despite this long history, PDE's role in envenomation remained enigmatic until Aird (2002) proposed that its function might be to release endogenous purines, which would immobilize the prey via hypotension and suppression of neurotransmitter release. Snake venom PDE has attracted great interest because of its utility in nucleic acid studies (>2,400 Medline citations). Despite its near reagent status, its structure is unknown. Most forms of PDE are membrane-bound or cytosolic, whereas venom PDE is extremely soluble, so as to function in the extracellular fluid of prey organisms. It has broad substrate specificity [Razzell and Khorana, 1959; Laskowski, 1980], making it well suited to the rapid liberation of adenosine nucleotides from various oligonucleotide precursors, a central theme in envenomation (Aird, 2002). It also has pyrophosphatase activity [Laskowski, 1980], releasing nucleotides and pyrophosphate from nucleoside triphosphates. Nucleotides are rapidly degraded to nucleosides by 5'-nuc!eotidase, present in both venom and prey tissues. Venom PDE was the first enzyme reported to have an active site threonine forming a covalent (phosphorylated) intermediate [Burgers et al., 1979; Gulp and Butler, 1986]. These functional characteristics suggest that it is likely to be structurally unique.

该建议包括两个使用类似方法的亚螺旋体。 1。哺乳动物二肽基肽酶IV （DPP IV）是一种高度糖基化的丝氨酸蛋白酶，可从寡肽中释放出N末端二肽。它 是整合膜蛋白（CD26）和血浆蛋白，其生理作用是 未知（Hosono et。，1999）。在其多种生理角色中，DPP IV删除了X-Pro，His-Ala或 来自诸如神经肽Y和物质的激素N末端的Tyr-Ala二肽。它是 Jorge Da Silva和Aird（2000）在蛇毒中发现。 DPP IV在毒液中的作用可能是为了防止 通过失活血管收缩性肽基，对抗性猎物的高血压反应 激素（Aird，2002）。它也可能有助于人类的持续性低血压 和发炎。本研究应阐明人类可溶性DPP IV的作用。 2。首先在毒液时发现裂解磷酸酯的蛇毒液 Gulland和Jackson（1938）报告了磷酸二酯酶（PDE）。尽管历史悠久，PDE的 直到Aird（2002）提出其功能可能是释放，在毒化中的作用一直是神秘的 内源性嘌呤，这将通过低血压和抑制来固定猎物 神经递质释放。蛇毒液PDE引起了极大的兴趣，因为它在核方面有用 酸性研究（> 2,400个MEDLINE引用）。尽管具有接近的试剂状态，但其结构还是未知的。最多 PDE的形式是膜结合或胞质的，而毒液PDE极易溶于 在猎物生物的细胞外液中的功能。它具有广泛的底物特异性[Razzell和Khorana， 1959年; Laskowski，1980年]，非常适合从各种腺苷核苷酸快速解放 寡核苷酸前体，毒化中的一个中心主题（Aird，2002）。它也有焦磷酸酶 活性[Laskowski，1980]，从三磷酸核苷中释放核苷酸和焦磷酸盐。 核苷酸通过5'-NUC！eotidase迅速降解为核苷，均存在于毒液和猎物中 组织。毒液PDE是第一个据报道具有活性位点苏氨酸的酶形成共价的 （磷酸化的）中级[Burgers等，1979; Gulp and Butler，1986]。这些功能 特征表明它可能在结构上是独一无二的。