Kvamme E, Torgner I A
Biochem J. 1974 Mar;137(3):525-30. doi: 10.1042/bj1370525.
Phosphate-activated glutaminase (EC 3.5.1.2; l-glutamine amidohydrolase) purified from pig kidney and brain is activated by CoA and short-chain acyl-CoA derivatives. Acetyl-CoA is the most powerful activator (K(A) about 0.2mm). Acetyl-CoA is maximally effective in the absence of other activating anions such as phosphate and citrate, and at low glutamine concentrations. The negative co-operative substrate activation observed at pH7 becomes more pronounced in the presence of acetyl-CoA. Similarly to phosphate, acetyl-CoA produces at high protein concentrations a different type of activation, which is time-dependent, depends on protein concentration and is accompanied by an increase in the sedimentation coefficient. Acetyl-CoA, phosphate and citrate appear to have binding sites in common. No significant difference was observed between kidney and brain phosphate-activated glutaminase.
从猪肾和脑中纯化得到的磷酸激活谷氨酰胺酶（EC 3.5.1.2；L-谷氨酰胺酰胺水解酶）可被辅酶A和短链酰基辅酶A衍生物激活。乙酰辅酶A是最有效的激活剂（K(A)约为0.2mM）。在没有其他激活阴离子如磷酸盐和柠檬酸盐的情况下，以及在谷氨酰胺浓度较低时，乙酰辅酶A的激活效果最佳。在pH7时观察到的负协同底物激活在乙酰辅酶A存在时变得更加明显。与磷酸盐类似，乙酰辅酶A在高蛋白浓度下会产生不同类型的激活，这种激活是时间依赖性的，取决于蛋白质浓度，并伴随着沉降系数的增加。乙酰辅酶A、磷酸盐和柠檬酸盐似乎有共同的结合位点。在肾和脑的磷酸激活谷氨酰胺酶之间未观察到显著差异。
