EFFECT OF AMINO ACIDS ON UTILIZATION OF SODIUM CASEINATE BY STREPTOCOCCUS LIQUEFACIENS AND STREPTOCOCCUS ZYMOGENES

Abstract

A strain of Streptococcus zymogenes and a strain of Streptococcus liquefaciens grew in a medium containing 10 amino acids and the latter organism was shown to produce an active proteinase in this medium. In the presence of glutamine and sodium caseinate, only five amino acids (glutamic acid, histidine, isoleucine, tryptophan, and valine) were required for growth. Under these conditions proteinase activity was barely demonstrable so that casein apparently was unable to induce proteinase synthesis to the same extent as were the five amino acids.