The Effect of Amino-Acids and Other Substances on the Activity of Streptococcal Hyaluronidase Crowley, Nuala,, 5, 906-918 (1951), doi = https://doi.org/10.1099/00221287-5-5-906, publicationName = Microbiology Society, issn = 1350-0872, abstract= SUMMARY: The titre of streptococcal polysaccharidase was increased by incubation with β-alanine, serine, tyrosine, cystine, cysteine or methionine. Dextrinogenic amylase and hyaluronidase measured by a turbidity end-point were both activated by cysteine, cystine, serine or methionine. Polysaccharidase activity also increased after incubation with hyaluronic acid, starch, pectin or dextran. Pantothenic acid suppressed activity of SH-activated enzymes, and the rise of titre observed during incubation with substrate was decreased twofold or fourfold by addition of valine. The activation of streptococcal proteinase by cysteine was also prevented or retarded by pantothenic acid or valine. Pantothenyl alcohol was more active than either pantothenate (dl-calcium salt)ordl-valine., language=, type=