Catabolite repression gene of Escherichia coli.

A catabolite repression gene (cat) which alters the sensitivity of Escherichia coli to catabolite repression has been mapped by transduction and shown to be located between the pyrC and purB genes. When the cat-1 mutation was studied in a number of genetic backgrounds, the results showed that this mutation affects the synthesis of more than one catabolic enzyme but does not completely eliminate catabolic repression under all conditions. It is suggested that this mutation may cause a block in the accumulation of the catabolite effector. Our experiments show that this effector is not glucose-6-phosphate.