STUDIES ON THE BIOSYNTHESIS OF THE M-PROTEIN OF GROUP A HEMOLYTIC STREPTOCOCCI

Abstract

Group A streptococci stripped of the M-protein antigen by treatment with trypsin reestablished the M-protein within an hour when incubated in a nutritionally rich medium. Under more defined conditions the utilization of amino acids for protein synthesis was dependent upon purine and pyrimidine bases, vitamins, and other accessory substances required for growth. Omission from the medium of certain amino acids known to be present in the M-protein, prevented the synthesis of the protein by washed trypsin-treated streptococci; omission of several amino acids not in the protein had no retarding effect. Polypeptides from a pancreatic digest of casein showed a marked stimulatory effect on M-protein synthesis in the absence of apparent cellular reproduction. Amino acids and glucose were required to supplement the peptides but no other constituents were necessary. Action of certain inhibitors of glycolysis and assimilation such as fluoride, arsenate, and dinitrophenol was observed with respect to M-protein synthesis.