title: Extracellular and membrane-bound proteases from Bacillus subtilis.
abstract: Bacillus subtilis YY88 synthesizes increased amounts of extracellular and membrane-bound proteases. More than 99% of the extracellular protease activity is accounted for by an alkaline serine protease and a neutral metalloprotease. An esterase having low protease activity accounts for less than 1% of the secreted protease. These enzymes were purified to homogeneity. Molecular weights of approximately 28,500 and 39,500 were determined for the alkaline and neutral proteases, respectively. The esterase had a molecular weight of approximately 35,000. Amino-terminal amino acid sequences were determined, and the actions of a number of inhibitors were examined. Membrane vesicles contained bound forms of alkaline and neutral proteases and a group of previously undetected proteases (M proteases). Membrane-bound proteases were extracted with Triton X-100. Membrane-bound alkaline and neutral proteases were indistinguishable from the extracellular enzymes by the criteria of molecular weight, immunoprecipitation, and sensitivity to inhibitors. The M protease fraction accounted for approximately 7% of the total activity in Triton X-100 extracts of membrane vesicles. The M protease fraction was partially fractionated into four species (M1 through M4) by ion-exchange chromatography. Immunoprecipitation and sensitivity to inhibitors distinguished membrane-bound alkaline and neutral proteases from M proteases. In contrast to alkaline and neutral proteases, proteases M2 and M3 exhibited exopeptidase activity.
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D000939:Epitopes; D004950:Esterases / Q000032:analysis / Q000096:biosynthesis; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000032:analysis / Q000096:biosynthesis / Q000276:immunology; D011480:Protease Inhibitors
chemical_list: D000939:Epitopes; D011480:Protease Inhibitors; D004950:Esterases; D010447:Peptide Hydrolases