KINETIC AND CHEMICAL MECHANISM OF ENZYMES

酶的动力学和化学机制

• 批准号: 3071147
• 负责人: PAUL F COOK
• 金额: $ 4.99万
• 依托单位: TEXAS COLLEGE OF OSTEOPATHIC MEDICINE
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-04-01 至 1988-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3071147
• 关键词: 6 phosphofructokinase; acidity /alkalinity; aspartate transaminase; chemical kinetics; chemical structure; enzyme model; enzyme structure; enzyme substrate; glutamate dehydrogenase; high performance liquid chromatography; malate dehydrogenase; nonradiation isotope effect; stable isotope; stoichiometry; ultraviolet spectrometry

The kinetic mechanism of an enzyme is determined in two parts: the order of addition of substrates and release of products and the location of slow steps along the reaction pathway. Techniques are available to obtain this information which include initial rate studies in the presence and absence of products and dead end inhibitors, isotope exchange at equilibrium, and isotope effect studies. More recent advances in steady state kinetic theory have shown that the chemical catalytic mechanism can also be obtained using a determination of the pH variation of primary and secondary isotope effects (particularly secondary effects which are more sensitive to transition state structure) and kinetic parameters (for example, Vmax, V/K, and Ki for a substrate or inhibitor). It is the goal of this project to determine the mechanism of action of enzymes which include malic enzyme from Ascaris suum (responsible for the oxidative decarboxylation of L-malate by DPN to pyruvate and CO2) using the approach outlined above. This kind of approach has been used with success for several enzymes including hexokinase and fructokinase but only a very small number of enzymes have mechanisms which are known with any degree of certainty.

酶的动力学机制由两部分决定： 底物的添加和产物的释放以及缓慢的位置 沿着反应路径的步骤。 可以使用技术来获得此 包括存在和不存在的初始速率研究的信息 产物和死端抑制剂、平衡时的同位素交换，以及 同位素效应研究。 稳态动力学的最新进展 理论表明，化学催化机理也可以是 通过测定初级和次级的 pH 值变化而获得 同位素效应（特别是对更敏感的次生效应） 过渡态结构）和动力学参数（例如，Vmax、V/K、 Ki 表示底物或抑制剂）。 该项目的目标是 确定酶（包括苹果酸酶）的作用机制 来自猪蛔虫（负责氧化脱羧 L-苹果酸通过 DPN 转化为丙酮酸和 CO2)，使用上述方法。 这种方法已成功用于多种酶 包括己糖激酶和果糖激酶，但只有极少数 酶具有任何程度的确定性已知的机制。