VITAMIN K, METABOLISM AND FUNCTION

维生素 K、新陈代谢和功能

• 批准号: 2596409
• 负责人: REIDAR WALLIN
• 金额: $ 24.09万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2002-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2596409
• 关键词: Sf9 cell line; carboxylation; chemical binding; chemical models; coagulation factor IX; coagulation factor VII; cofactor; decarboxylases; drug resistance; enzyme complex; enzyme reconstitution; glutathione transferase; laboratory rabbit; laboratory rat; molecular site; oxidoreductase; pharmacokinetics; polymerase chain reaction; posttranslational modifications; protein biosynthesis; protein sequence; protein structure function; vitamin K; vitamin metabolism; warfarin

DESCRIPTION: Understanding vitamin K-dependent proteins will require insight into their biosynthesis and regulation. Unique for these proteins is their vitamin K-dependent post-translational modification. The modification is carried out by the _-carboxylase, an integral protein of the ER membrane which uses the reduced form of vitamin K (vitamin KH2) as cofactor. The reduced cofactor is produced by the enzyme Vitamin K 3,4-Epoxide reductase (VKOR) which is the target for the anticoagulant drug warfarin. Despite numerous attempts to purify VKOR, the molecular components that constitute the enzyme have not been identified. The applicants have been able to show that VKOR is an enzyme complex in the ER membrane and they propose that assembly of the complex is similar to assembly of the lipoxygenase complex on the nuclear envelope membrane. Both enzymes incorporates a member of the glutathione-S-transferase gene family as part of the lipid-protein enzyme complex. Experiments are proposed to complete the model of the VKOR enzyme complex and unveil the basis for genetic resistance to warfarin. Recombinant VKOR will be used to increase the capacity of cell lines to produce functional clotting factors VII and IX. It is our hypothesis that vitamin KH2 cofactor production by VKOR is a limiting factor in cellular production of these recombinant proteins. Although 8-10 different vitamin K-dependent proteins have been shown to be made extrahepatically only some have been identified. They include the coagulation factors prothrombin and protein S, the growth arrest specific gene 6 product Gas6 and the bone and cartilage resident proteins, osteocalsin and matrix GLA protein (MGP). In the last specific aim of this application experiments are proposed to identify new vitamin K-dependent proteins by vitamin K-dependent radioactive labeling. The proposed experiments will provide a better understanding of vitamin K metabolism and vitamin K function and have an impact on prophylactic medicine concerned with recombinant vitamin K-dependent coagulation factors and warfarin anticoagulation. The experiments should also contribute to the exciting, rapidly expanding area of research on extra-hepatic vitamin K-dependent proteins.

描述：了解维生素K依赖性蛋白需要 深入了解其生物合成和调节。 这些蛋白质独特 是他们的维生素K依赖性后翻译后修饰。 这 修饰是由_-羧化酶进行的，_-羧化酶是一种积分蛋白 ER膜使用降低的维生素K（维生素KH2）作为 辅因子。 还原的辅因子是由酶维生素K产生的 3,4-环氧还原酶（VKOR）是抗凝药物的靶标 华法林。 尽管尝试纯化VKOR，但分子 尚未确定构成酶的成分。 这 申请人已经能够证明VKOR是ER中的酶复合物 膜，他们建议该综合体的组装类似于 脂氧合酶复合物在核包膜膜上的组装。 两个都 酶结合了谷胱甘肽-S-转移酶基因家族的成员 作为脂质蛋白酶复合物的一部分。 提出了实验 完成VKOR酶复合物的模型，并揭示了基础 对华法林的遗传抵抗。 重组VKOR将用于增加 细胞系产生功能性凝血因子VII和 ix。 我们的假设是，Vkor生产维生素KH2辅因子是 这些重组蛋白的细胞产生的限制因子。 尽管8-10种不同的维生素K依赖性蛋白已显示为 外态度仅确定了一些。 他们包括 凝血因子凝血酶原和蛋白质S，生长阻滞特异性 Gene 6产品GAS6和骨骼和软骨常驻蛋白， 骨内胶质素和基质GLA蛋白（MGP）。 在最后的特定目标中 提出了应用实验来识别新的维生素K依赖性 维生素K依赖性放射性标记的蛋白质。 提议 实验将更好地了解维生素K代谢和 维生素K功能，对有关的预防医学有影响 重组维生素K依赖性凝血因子和华法林 抗凝。 实验还应有助于令人兴奋的， 依赖肝外维生素K依赖性的研究领域快速扩展 蛋白质。