Hood W, de la Morena E, Grisolia S
Acta Biol Med Ger. 1977;36(11-12):1667-72.
Glutamate dehydrogenase is very susceptible to carbamylation which results in loss of activity. The effect of a number of proteolytic enzymes (pronase, trypsin and chymotrypsin) on native and carbamylated glutamate dehydrogenase was tested. In all cases, the carbamylated enzyme was at least twice as susceptible to proteolysis as the native enzyme. Antibodies were prepared against glutamate dehydrogenase and carbamylated glutamate dehydrogenase; the carbamylated enzyme was antigenically indistinguishable from the native enzyme. Preliminary experiments indicate that the carbamylated glutamate dehydrogenase is taken up by ascites tumor cells while glutamate dehydrogenase is not. It seems possible that the effects described can be extrapolated to degradation by lysosomes and to other covalently modified enzymes.
谷氨酸脱氢酶极易发生氨甲酰化，这会导致其活性丧失。测试了多种蛋白水解酶（链霉蛋白酶、胰蛋白酶和胰凝乳蛋白酶）对天然和氨甲酰化谷氨酸脱氢酶的作用。在所有情况下，氨甲酰化酶对蛋白水解的敏感性至少是天然酶的两倍。制备了针对谷氨酸脱氢酶和氨甲酰化谷氨酸脱氢酶的抗体；氨甲酰化酶与天然酶在抗原性上无法区分。初步实验表明，腹水肿瘤细胞会摄取氨甲酰化谷氨酸脱氢酶，而不会摄取谷氨酸脱氢酶。所述效应似乎有可能外推至溶酶体降解以及其他共价修饰的酶。
