Simultaneous induction of three catabolic enzymes in Escherichia coli

Abstract

During a simultaneous induction of three enzymes which are subject to catabolite repression (beta-galactosidase, tryptophanase and amylomaltase, or beta-galactosidase, tryptophanase and D-serine deaminase) in a batch culture, the rates of synthesis of beta-galactosidase and tryptophanase decreases, while the rates of synthesis of amylomaltase and D-serine deaminase remain unaffected. The addition of cAMP brings about a considerable increase of the rate of synthesis of D-serine deaminase and a partial synthesis rate increase of beta-galactosidase whihle the synthesis rate of tryptophanase remains lowered and the synthesis rate of amylomaltase remains unaffected. In a continuous culture beta-galactosidase, tryptophanase and D-serine deaminase are synthesized simultaneously at a maximum rate without mutual influence. The addition of cAMP increases the rate of synthesis of all three enzymes.