title: Natural phosphorylation of group A streptococcal pyrogenic exotoxin type C.
abstract: Group A streptococcal pyrogenic exotoxin (SPE) type C, produced by strain T18P grown in the presence of 32P, was separated from culture supernatant fluids by using alcohol precipitation. The resulting toxin (EtOH-1) contained 3 X 10(6) to 5 X 10(6) cpm of 32P per milligram of protein. The radiolabel migrated with SPE C during isoelectric focusing in polyacrylamide gels (pI 6.7) and double immunodiffusion, in which the toxin formed a line of identity with highly purified SPE C when reacted with hyperimmune antisera raised against SPE C. The EtOH-1 radiolabeled toxin was pyrogenic and had the capacity to enhance host susceptibility to lethal endotoxin shock. EtOH-1 toxin lost both radiolabel and biological activity after being treated with alkaline phosphatase. The nonspecific lymphocyte mitogenicity of purified unlabeled SPE C was stimulated by adenosine monophosphate but not adenosine, adenosine diphosphate, or adenosine triphosphate. Adenosine monophosphate may function as a cofactor of SPE C and contribute the phosphate group required for biological activity.
mesh_terms: D000249:Adenosine Monophosphate / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000494:pharmacology; D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D005098:Exotoxins / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology; D005779:Immunodiffusion; D007525:Isoelectric Focusing; D008213:Lymphocyte Activation / Q000187:drug effects; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011817:Rabbits; D013297:Streptococcus pyogenes / Q000032:analysis / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D005098:Exotoxins; D010761:Phosphorus Radioisotopes; D000249:Adenosine Monophosphate; D000469:Alkaline Phosphatase