title: Yeast mutants with enhanced ability to secrete human lysozyme: isolation and identification of a protease-deficient mutant.
abstract: Yeast mutant strains which secrete large amounts of human lysozyme were screened using an agar medium containing bacterial cells. Nine mutants secreted over 10 times more lysozyme than the wild-type parent strain. The mRNA levels for lysozyme in the mutants were not higher than that of the wild-type strain. Three of the mutant strains were deficient in carboxypeptidase Y activity. It was found that the protease deficiency was caused by a deficiency in conversion of proenzyme to mature enzyme in ssl1 mutant cells. The ssl1 gene was found to be closely linked to the centromere and determine both the efficiency of secretion of lysozyme and the processing of carboxypeptidase Y.
authors.affiliation: Biological Chemistry Division, National Chemical Laboratory for Industry, Ibaraki, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Ichikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Jigami
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D002268:Carboxypeptidases / Q000378:metabolism*; D043402:Cathepsin A; D002503:Centromere; D003433:Crosses, Genetic; D005800:Genes, Fungal; D008040:Genetic Linkage; D006801:Humans; D009113:Muramidase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011498:Protein Precursors; D012333:RNA, Messenger / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D011498:Protein Precursors; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D009113:Muramidase; D002268:Carboxypeptidases; D043402:Cathepsin A; C499283:PRC1 protein, S cerevisiae; C022633:serine carboxypeptidase