REACTION MECHANISMS FOR ENZYMES

酶的反应机制

• 批准号: 3486037
• 负责人: JULES Alan SHAFER
• 金额: $ 26.62万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-04-01 至 1991-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3486037
• 关键词: Escherichia coli; calcium; chemical fingerprinting; chemical structure function; cysteine; enzyme mechanism; enzyme model; enzyme structure; enzyme substrate complex; fibrin; fibrin stabilizing factor; fibrinogen; glycine; high performance liquid chromatography; human subject; human tissue; molecular pathology; nuclear magnetic resonance spectroscopy; protein engineering; protein sequence; site directed mutagenesis; thrombin; thrombosis

Papain, a thiol protease from papaya latex, will be studied to determine the role of Asp-158 in catalysis and to determine the effect of Asp-158 on the interactive ionization of His-159 and Cys-25 at the active site of papain. Derivatives of papain modified at Asp-158 will be prepared and characterized with respect to their altered interactions with substrates and inhibitors. Proton NMR and potentiometric difference titrations will be used to determine alterations in the ionization behavior of His-159 and Cys-25 caused by modification of Asp-158. The interactive ionization of His-159 and Cys-25 also will be investigated to determine the effect of the ion-pair interaction on the reactivity of these residues. The nucleophilic reactivity of ammonium-thiolate ion-pairs in nonenzymic reactions will be studied to evaluate the possible catalytic advantage of the imidazolium-thiolate ion-pair at the active site of papain. The potentiometric difference titration method we have developed for determining the ionization behavior of the thiol group in papain will be used to determine the possible existence of ligand dependent ionic interactions involving Cys-beta 93 of hemoglobin. D-Serine dehydratase from E. coli will be studied to determine a) how monovalent cations effect the affinity of the enzyme for its cofactor pyridoxal 5'-phosphate, b) the involvement of a thiol group in the catalytic activity of the enzyme, and c) the intermediates in the catalytic pathway and their rates of interconversion. Studies with human fibrinogen from individuals with dysfibrinogenemia are proposed in which amino acid replacements in abnormal fibrinogens will be related to their altered functional competence especially their altered interactions with the enzymes involved in blood clot formation dissolution.

木瓜蛋白酶是一种从木瓜胶乳中提取的巯基蛋白酶

项目成果

Inactivation of D-serine dehydratase by alkylamines via a transimination of enzyme-linked cofactor.

烷基胺通过酶联辅因子的转氨作用灭活 D-丝氨酸脱水酶。

• 发表时间: 1981
• 期刊: The Journal of biological chemistry
• 作者: Federiuk,CS;Shafer,JA
• 通讯作者: Shafer,JA

Fibrinogen Petoskey: identification of a new dysfibrinogenemia characterized by altered release of fibrinopeptide A.

纤维蛋白原 Petoskey：鉴定一种新的异常纤维蛋白原血症，其特征是纤维蛋白肽 A 释放改变。

• DOI: 10.1016/0049-3848(81)90173-0
• 发表时间: 1981
• 期刊: Thrombosis research
• 影响因子: 7.5
• 作者: Higgins,DL;Penner,JA;Shafer,JA
• 通讯作者: Shafer,JA

A reaction pathway for transimination of the pyridoxal 5'-phosphate in D-serine dehydratase by amino acids.

D-丝氨酸脱水酶中吡哆醛 5-磷酸通过氨基酸转亚胺化的反应途径。

• 发表时间: 1983
• 期刊: The Journal of biological chemistry
• 作者: Federiuk,CS;Shafer,JA
• 通讯作者: Shafer,JA

Steady state kinetic parameters for the thrombin-catalyzed conversion of human fibrinogen to fibrin.

凝血酶催化人纤维蛋白原转化为纤维蛋白的稳态动力学参数。

• 发表时间: 1983
• 期刊: The Journal of biological chemistry
• 作者: Higgins,DL;Lewis,SD;Shafer,JA
• 通讯作者: Shafer,JA

Characterization of the catalytic pathway for D-serine dehydratase. Evidence for variation of the rate-determining step with substrate structure.

D-丝氨酸脱水酶催化途径的表征。

• 发表时间: 1983
• 期刊: The Journal of biological chemistry
• 作者: Federiuk,CS;Bayer,R;Shafer,JA
• 通讯作者: Shafer,JA