title: Properties of extracellular neuraminidase produced by group A streptococcus.
abstract: Extracellular neuraminidase production by group A streptococci was examined in 92 strains. Fourteen of these strains produced appreciable amounts of enzyme; 12 of the neuraminidase-producing strains belonged to T types 1, 4, and 12. Production of the enzyme paralleled bacterial growth in culture and was maximal in medium containing 0.2% glucose. The enzyme produced by one of these strains was partially purified by ammonium sulfate fractionation and filtration on G-200 Sephadex. Its molecular weight was estimated at 90,000. Activity was optimal at pH 5.7 and in the presence of 0.01 to 0.03 M calcium and magnesium cations. The enzyme was stable at temperatures of 4 and 37 degrees C for at least 24 h but was inactivated within 10 min at temperatures of 50 and 65 degrees C. The enzyme hydrolyzed 40% of the sialic acid in bovine submaxillary mucin, but was inactive on sialyl-lactose, porcine submaxillary mucin, oligosaccharides derived from porcine mucin, or human orosomucoid. The Km value for this enzyme with bovine submaxillary mucin as substrate was in the order of 3.6 x 10(-4) M.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009077:Mucins / Q000378:metabolism; D009439:Neuraminidase / Q000302:isolation & purification / Q000378:metabolism*; D013297:Streptococcus pyogenes / Q000201:enzymology* / Q000254:growth & development; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D009077:Mucins; D009439:Neuraminidase; D008274:Magnesium; D002118:Calcium