title: Maturation of vacuolar (lysosomal) enzymes in yeast: proteinase yscA and proteinase yscB are catalysts of the processing and activation event of carboxypeptidase yscY.
abstract: Studies were performed to unravel the activation and maturation mechanism of vacuolar (lysosomal) proteinases in Saccharomyces cerevisiae. In vivo and in vitro studies show that proteinase yscA and proteinase yscB are involved in the activation and processing event of pro-carboxypeptidase yscY. Processing and activation of pro-carboxypeptidase yscY by proteinase yscA depends on an additional factor contained in the vacuolar fraction. Comparable activation can be mimicked by sodium polyphosphate. Optimum pH for processing by this proteinase yscA-triggered event is 5. The proteinase yscA-triggered maturation process of pro-carboxypeptidase yscY leads to an intermediate mol. wt form of the enzyme which is, however, fully active. Proteinase yscB transfers the intermediate mol. wt form of the original precursor to the apparently authentic, mature and active carboxypeptidase yscY. An activation and maturation scheme is devised.
authors.affiliation: Biochemisches Institut, Universität Freiburg, FRG.
authors.forename: B
authors.initials: B
authors.lastname: Mechler
authors.forename: H
authors.initials: H
authors.lastname: Müller
authors.forename: D H
authors.initials: DH
authors.lastname: Wolf
mesh_terms: D016282:Aspartic Acid Endopeptidases; D002268:Carboxypeptidases / Q000235:genetics / Q000378:metabolism*; D043402:Cathepsin A; D010450:Endopeptidases / Q000378:metabolism*; D004789:Enzyme Activation; D007700:Kinetics; D008247:Lysosomes / Q000201:enzymology; D009154:Mutation; D009940:Organoids / Q000201:enzymology*; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D002268:Carboxypeptidases; D010450:Endopeptidases; D043402:Cathepsin A; C499283:PRC1 protein, S cerevisiae; C022633:serine carboxypeptidase; D012697:Serine Endopeptidases; C023302:yeast proteinase B; C022325:aspartic proteinase A; C499267:PEP4 protein, S cerevisiae; D016282:Aspartic Acid Endopeptidases