title: Phosphate-mediated alteration of the Microsporum gypseum germination protease specificity for substrate: enhanced keratinase activity.
abstract: Inorganic phosphate was found to decrease the caseinolytic and ethyl-esterase activities of the Microsporum gypseum germination protease. The germination protease possessed exokeratinase (beta-keratinase) activity immediately after release from the fungal spore. After phosphate treatment of the enzyme, the germination protease also possessed endo-keratinase (alpha-keratinase) activity. Phosphate altered the protease's pH optimum from 9.0 to 7.0 and decreased the molecular weight from 33,000 to 16,000. These values were identical to those found for the keratinase. Alpha- and beta-keratinase activities were stimulated in excess of 200-fold by disulfide reducing agents. Natural and suspected keratin degradation products also enhanced keratinase activity. Cell fractionation and in vitro conversion of the alkaline germination protease into a functional keratinase suggested that the subunits comprising the germination protease and the keratinase were of a common origin.
mesh_terms: D000818:Animals; D002364:Caseins / Q000378:metabolism; D002645:Chickens; D002845:Chromatography; D003545:Cysteine / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism*; D004790:Enzyme Induction; D004950:Esterases / Q000378:metabolism; D005241:Feathers; D006168:Guinea Pigs; D006197:Hair; D006736:Horses; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007633:Keratins / Q000378:metabolism; D008864:Microsporum / Q000201:enzymology* / Q000254:growth & development; D008954:Models, Biological; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000378:metabolism*; D010710:Phosphates / Q000494:pharmacology*; D013172:Spores, Fungal / Q000254:growth & development; D013447:Sulfites / Q000494:pharmacology
chemical_list: D002364:Caseins; D009097:Multienzyme Complexes; D010710:Phosphates; D013447:Sulfites; D007633:Keratins; D004950:Esterases; D010450:Endopeptidases; D003545:Cysteine; D004229:Dithiothreitol