Entian K D
Mol Gen Genet. 1980;178(3):633-7. doi: 10.1007/BF00337871.
Mutants with reduced hexokinase activity previously isolated as resistant to carbon catabolite repression of invertase and maltase (Zimmermann and Scheel, 1977) were allele tested with mutant strains of Lobo and Maitra (1977) which had defects in one or several of the genes coding for glucokinase and the two unspecific hexokinases. It could be demonstrated, that the mutation abolishing carbon catabolite repression had occurred in a gene allelic to the structural gene of hexokinase PII. Moreover, the defective mutant allele for hexokinase PII isolated by Lobo and Maitra (1977) was also defective in carbon catabolite repression. Neither glucokinase nor hexokinase PI showed any effect on this regulatory system. Biochemical analysis in crude extracts also showed altered kinetic properties of hexokinases in the hex1 mutants. The results directly support the hypothesis previously put forward, that one of the hexokinases is not only active as a catalytic, but also as a regulatory protein.
先前分离出的己糖激酶活性降低的突变体，对蔗糖酶和麦芽糖酶的碳分解代谢物阻遏具有抗性（齐默尔曼和舍尔，1977年），用洛博和迈特拉（1977年）的突变菌株进行了等位基因测试，这些菌株在编码葡萄糖激酶和两种非特异性己糖激酶的一个或几个基因中存在缺陷。结果表明，消除碳分解代谢物阻遏的突变发生在与己糖激酶PII结构基因等位的一个基因中。此外，洛博和迈特拉（1977年）分离出的己糖激酶PII缺陷突变等位基因在碳分解代谢物阻遏方面也存在缺陷。葡萄糖激酶和己糖激酶PI对该调节系统均无任何影响。粗提物中的生化分析还表明，hex1突变体中己糖激酶的动力学特性发生了改变。这些结果直接支持了先前提出的假设，即其中一种己糖激酶不仅作为催化蛋白具有活性，而且作为调节蛋白也具有活性。
