BRAIN GLUTAMATE DEHYDROGENASE--CHARACTERIZATION IN YOUNG AND OLD RATS

这项实验调查将扩展我们目前的研究，以包括 黄曲霉谷氨酸脱氢酶的性质研究 幼鼠的大脑和老年大鼠的大脑。这一特征将 允许确定大鼠的衰老是否会导致 这种酶。比活度、热稳定性、净变化、末端 该酶的氨基酸基团和胰蛋白酶多肽图谱 将两个老年组的大鼠进行比较。的特定活动 酶的测定将基于每毫克的酶活性 蛋白质和每单位抗血清。针对这种酶的抗体将会是 由免疫兔子制备。更详细的动力学分析也将 取各年龄组大鼠分离的酶进行处理。这一分析 将包括测定底物的米氏常数和 辅酶为酶，考查酶与酶的关系 活性与pH的关系，利用竞争性绘制活性部位图 抑制剂和替代底物，以及变构的检查 酶活性中的效应器。这种详细的动力学分析将 为评估酶的构象差异提供了一个有价值的工具 这是对衰老生物体的酶分子的假设，并将给出 洞察监管模式中可能存在的差异。

This experimental investigation will extend our present studies to include a characterization of the enzyme glutamate dehydrogenase isolated from brains of young rats and brains of old rats. This characterization will permit a determination as to whether ageing in rat result in alterations of this enzyme. The specific activity, heat stability, net change, terminal amino acid groups, and tryptic peptide mapping of the enzyme isolated from rats of the two aged groups will be compared. The specific activity of the enzyme will be determined both on the basis of enzyme activity per mg of protein and per unit of antiserum. Antibodies against the enzyme will be prepared by immunizing rabbits. A more detailed kinetics analysis will also be performed on enzyme isolated from rats of each age group. This analysis will include a determination of Michaelis constants for the substrates and coenzymes for the enzyme, an examination of the relationship of enzymic activity with pH, mapping of the active site utilizing competitive inhibitors and alternate substrates, and an examination of allosteric effectors in enzymic activity. This kind of detailed kinetic analysis will provide a valuable tool in assessing conformational differences in enzyme which is hypothesized for enzyme molecules of aged organisms and will give insight into possible differences in regulatory patterns.