title: Yeast KEX1 gene encodes a putative protease with a carboxypeptidase B-like function involved in killer toxin and alpha-factor precursor processing.
abstract: The yeast KEX1 gene product has homology to yeast carboxypeptidase Y. A mutant replacing serine at the putative active site of the KEX1 protein abolished activity in vivo. A probable site of processing by the KEX1 product is the C-terminus of the alpha-subunit of killer toxin, where toxin is followed in the precursor by 2 basic residues. Processing involves endoproteolysis following these basic residues and trimming of their C-terminal by a carboxypeptidase. Consistent with the KEX1 product being this carboxypeptidase is its role in alpha-factor pheromone production. In wild-type yeast, KEX1 is not essential for alpha-factor production, as the final pheromone repeat needs no C-terminal processing. However, in a mutant in which alpha-factor production requires a carboxypeptidase, pheromone production is KEX1-dependent.
authors.forename: A
authors.initials: A
authors.lastname: Dmochowska
authors.forename: D
authors.initials: D
authors.lastname: Dignard
authors.forename: D
authors.initials: D
authors.lastname: Henning
authors.forename: D Y
authors.initials: DY
authors.lastname: Thomas
authors.forename: H
authors.initials: H
authors.lastname: Bussey
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002268:Carboxypeptidases / Q000235:genetics; D043402:Cathepsin A; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D005800:Genes, Fungal; D055646:Killer Factors, Yeast; D000072235:Mating Factor; D010452:Peptide Biosynthesis; D010455:Peptides; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011506:Proteins; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid
chemical_list: D005656:Fungal Proteins; D055646:Killer Factors, Yeast; D010455:Peptides; D011498:Protein Precursors; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D000072235:Mating Factor; D002268:Carboxypeptidases; D043402:Cathepsin A; C499283:PRC1 protein, S cerevisiae; C022633:serine carboxypeptidase