Sundaram T K, Fincham J R
J Bacteriol. 1968 Mar;95(3):787-92. doi: 10.1128/jb.95.3.787-792.1968.
The mutant am-14 produces no active nicotinamide adenine dinucleotide phosphate-linked glutamate dehydrogenase (GDH) and no protein showing immunological cross-reaction with the enzyme. Nevertheless, it shows complementation with several other am mutants in heterokaryons. Active GDH can be extracted from heterokaryons formed from am-14 and other mutants which, by themselves, produce more or less inactive varieties of the enzyme. The enzyme from am-14 + am-3 heterokaryons can be partially separated from am-3 mutant GDH on a diethylaminoethyl cellulose column. It is characterized by abnormally high thermolability and by a capacity for activation by glutamate. By the same procedure as brings about hybridization between mutant GDH proteins, it has been possible to recover enzyme with the properties of pure am-3 GDH from a partially purified am-14 + am-3 GDH preparation which was initially substantially free of unhybridized am-3 enzyme. This is interpreted as evidence that the active complementation product is a hybrid oligomer containing am-3 monomers and also am-14 monomers, the latter being unable to aggregate by themselves. Heterokaryons formed from am-14 and wild type produce GDH of abnormally high thermolability, presumably due to the formation of am-14 + am(+) hybrids.
突变体am - 14不产生有活性的烟酰胺腺嘌呤二核苷酸磷酸连接的谷氨酸脱氢酶（GDH），也不产生与该酶有免疫交叉反应的蛋白质。然而，它在异核体中与其他几个am突变体表现出互补作用。活性GDH可以从由am - 14和其他突变体形成的异核体中提取出来，而这些突变体自身产生的酶或多或少是无活性的。来自am - 14 + am - 3异核体的酶可以在二乙氨基乙基纤维素柱上与am - 3突变体GDH部分分离。其特点是热稳定性异常高，且具有被谷氨酸激活的能力。通过与突变体GDH蛋白进行杂交的相同程序，已能够从最初基本不含未杂交的am - 3酶的部分纯化的am - 14 + am - 3 GDH制剂中回收具有纯am - 3 GDH特性的酶。这被解释为活性互补产物是一种包含am - 3单体和am - 14单体的杂合寡聚物的证据，后者自身无法聚集。由am - 14和野生型形成的异核体产生热稳定性异常高的GDH，推测是由于形成了am - 14 + am(+)杂种。
