BRAIN GLUTAMATE DEHYDROGENASE--CHARACTERIZATION IN YOUNG AND OLD RATS

这项实验研究将扩展我们目前的研究，包括 谷氨酸脱氢酶的特性，分离自 年轻老鼠和老年老鼠的大脑。这种特性将 允许确定大鼠的老化是否导致 这种酶。比活度、热稳定性、净变化、终末 氨基酸组，和胰蛋白酶肽图谱的酶分离自 将两个老龄组的大鼠进行比较。的比活性 酶将基于每毫克的酶活性来确定， 蛋白质和每单位抗血清。针对这种酶的抗体将被 通过免疫兔子制备。更详细的动力学分析也将 对从每个年龄组的大鼠中分离的酶进行。该分析 将包括测定底物的米氏常数， 辅酶的酶，酶的关系的检查 活性与pH，利用竞争性的活性位点的映射 抑制剂和替代底物，并检查变构 酶活性的效应子。这种详细的动力学分析将 提供了一个有价值的工具，在评估构象差异的酶 这是假设为酶分子的老化有机体， 深入了解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.