title: Cysteine protease activity of streptococcal pyrogenic exotoxin B.
abstract: Streptococcal pyrogenic exotoxin B (SPE B) was purified and its protease and mitogenic activities were investigated. The apparent molecular mass of SPE B purified in the presence of iodoacetic acid was 42 kDa, whereas 29-kDa SPE B was predominant without the reagent. A polyclonal antibody raised against the 29-kDa species reacted with both species, indicating that the 42-kDa species was a precursor of the 29-kDa entity. Both the 42- and 29-kDa species enhanced [3H]thymidine incorporation into human peripheral blood mononuclear cells, whereas neither had any effect on T cell depleted mononuclear cells. The 29-kDa SPE B possessed caseinolytic activity, with an optimal pH of 8, and the activity was specifically suppressed by the antibody. A group of cysteine protease inhibitors, but no serine-, metallo-, or acidic-protease inhibitors, limited the protease activity, whereas dithiothreitol increased the activity. The DNA sequence around a putative active cysteine residue was identical among the speB genes from Streptococcus pyogenes R70, NY-5, and T19. Taken together, these results indicate that SPE B is identical to a cysteine protease, streptopain (EC 3.4.22.10).
authors: Department of Microbiology, School of Dentistry, Iwate Medical University, Morioka, Japan.
authors: Y
authors: Y
authors: Ohara-Nemoto
authors: M
authors: M
authors: Sasaki
authors: M
authors: M
authors: Kaneko
authors: T
authors: T
authors: Nemoto
authors: M
authors: M
authors: Ota
mesh_terms: D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D005098:Exotoxins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D007963:Leukocytes, Mononuclear; D008565:Membrane Proteins; D008934:Mitogens / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013297:Streptococcus pyogenes / Q000737:chemistry* / Q000201:enzymology*
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D015853:Cysteine Proteinase Inhibitors; D005098:Exotoxins; D008565:Membrane Proteins; D008934:Mitogens; C117980:SpeA protein, Streptococcus pyogenes; C027951:erythrogenic toxin; D003546:Cysteine Endopeptidases; C042477:streptopain; D004229:Dithiothreitol