| 摘要 |
PURPOSE:To obtain a variant of yeast capable of producing peptide or protein at low cost, partially or wholly deficient in a gene of an enzyme of converting or hydrolyzing galactose by transforming the yeast cells of a strain with a gene having exogeneous peptide, etc., in order to prepare the subject variant cells. CONSTITUTION:GAL 1 gene is taken out from a complex plasmid cloned with preferably galactokinase gene (GAL 1 gene), the central part of the gene is cleft with a proper restriction enzyme, a DNA fragment having an arbitrary size is cut out, the gene is partially replaced by integration with orotidine-5- phosphate decarboxylase gene, the recombinant DNA fragment is transduced to the cells of a yeast strain (preferably Saccharomyces cerevisiae) to give the objective variant cells of yeast partially or wholly deficient in the yeast gene of an enzyme capable of converting or hydrolyzing galactose. The variant is transformed with a gene of self- or exogeneous peptide or protein and the transformant is cultured at 20-30 deg.C in a galactose-containing medium (pH 4-8) to collect peptide or protein. |
