Factors Underlying Bacterial Enzyme Synthesis. ∗

Abstract

Summary

1. A marked stimulation of the synthesis of formic hydrogenlyase by E. coli in the presence of sodium formate and peptone is brought about by addition of either DLaspartate, fumarate, or nitrate under conditions when little or no proliferation takes place. Addition of succinate produces no effect. Sone of these compounds stimulates activity of the enzyme in pre-adapted cells. Whilst a mixture of glycerol and peptone, or a mixture of fumarate and peptone does not secure enzyme synthesis, a mixture of glycerol, fumarate and peptone is effective. The energy for synthesis in resting cells may thus be obtained by the interaction of suitable hydrogen donors and hydrogen acceptors. Aspartate is effective presumably because it is converted by aspartase into fumarate. This conclusion is supported by the fact that the presence of ammonium ions inhibits adaptation in a formate-peptone medium, but not in a glucose-amino acid medium where energy is secured by glucose breakdown. 2 . Certain amino acids are required for the enzyme synthesis. The most effective are leucine. aspartate, histidine, and serine. Requirements for specific amino acids appear to vary with the strain of the organism.