The mechanism of the synthesis of enzymes. I. Development of a system suitable for studying this phenomenon.

1. An experimental system suitable for the study of enzyme formation has been described. 2. The formation of beta-galastosidase in E. coli B could be induced by lactose, melibiose, D-galactose and beta-methyl-D-galactoside. 3. Lactose-induced beta-galactosidase formation was found to be inhibited by D-glucose, D-mannose, D-fructose, D-arabinose, and raffinose. 4. The utilizable structural analogue, D-glucose, was found to either stimulate or inhibit beta-galactosidase formation depending upon its concentration. D-Arabinose, on the other hand, a non-utilizable structural analogue, is only capable of inhibiting, whereas succinic acid, a structurally unrelated energy source, is only capable of stimulating beta-galactosidase formation. 5. D-Arabinose inhibition of lactose-induced beta-galactosidase formation was found to be of the competitive type. 6. Some of the implications of these findings have been discussed.