Repression and De-repression of Enzyme Synthesis as a Possible Explanation of some Aspects of Drug Action

ACCORDING to recent theories, the induction of enzyme synthesis occurs as a result of the displacement from an enzyme-forming system of a natural repressor 1 . For example, the synthesis of alkaline phosphatase by E. coli is normally repressed by inorganic phosphate 2 . De-repression occurs when there is only a small amount of inorganic phosphate in the medium. The repressor theory is in good agreement with most of the observations which have been made on enzyme-inducing systems. The inducer need not be a substrate for the enzyme which is formed, nor need it serve as a template for the formation of new enzymes 1 .