title: The characteristics of M proteins purified by column chromatography with hydroxyapatite from acid extracts of Streptococcus pyogenes of types 1, 3, 6, 12 and 17.
abstract: Purified M proteins were recovered from acid extracts of Streptococcus pyogenes, M-types 1, 3, 6, 12 and 17, by elution from columns of hydroxyapatite of the proteins precipitated with ammonium sulphate. M protein free from non-type-specific antigens was recovered only from M-type 12. Although similar fractions were not recovered from M-types 1, 3, 6 and 17, purified preparations containing a single cross-reactive antigen were obtained. In addition to the M proteins associated with cross-reactive antigens, type-specific antigens that did not stimulate opsonic antibodies were isolated from revealed molecular weights that ranged from 32,000  to 63,000 daltons, total amino acid compositions that were similar, and N-terminal amino acids that were variable.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis / Q000276:immunology; D002845:Chromatography / Q000379:methods; D006801:Humans; D008970:Molecular Weight; D009895:Opsonin Proteins / Q000096:biosynthesis; D011817:Rabbits; D013290:Streptococcal Infections / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000032:analysis* / Q000276:immunology
chemical_list: D000596:Amino Acids; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D009895:Opsonin Proteins