The Degradation of Starch by Strains of Group A Streptococci having Related Antigens

SUMMARY: Strains of Group A streptococci produced an extracellular carbohydrase which degraded starch. The enzyme in crude undialysed culture filtrates bore a general resemblance to pancreatic diastase. Amylolytic activity was decreased in environmental conditions which also affected streptococcal proteinase, namely in cultures grown at 23°, in filtered broth, or after serial mouse passage. Amylase production was associated with hyaluronidase production in strains having the type-specific M antigen 4, or the non-specific T antigen 4, whereas proteinase-positive strains of the same group of closely related specific Types 4, 24, 26, 28, 29, 46 were usually amylase-negative; but the association between production of any two of the three enzymes was not complete. Hyaluronidase-positive Type 22 strains did not produce amylase, and with two exceptions, a Type 2 strain and a strain serologically unidentified, other representative serological types were amylase-negative, though some strains degraded starch in growing cultures.