Expression of the carboxymethylcellulase gene, CMC1, from Cryptococcus flavus in Saccharomyces cerevisiae

A cDNA copy of the carboxymethylcellulase (CMCase 1) gene, CMC1, of the yeast Cryptococcus flavus was expressed in Saccharomyces cerevisiae under the control of the glyceraldehyde-3-phosphate dehydrogenase gene ( GAP) promoter derived from S. cerevisiae. In glucose medium, extracellular production of a large amount of CMCase 1 was achieved by S. cerevisiae cells transformed with YEp-plasmid carrying CMC1. Two major proteins (36 kDa and 34 kDa) secreted in the medium both had CMCase activity and immuno-responsibility to anti-CMCase 1-antibody. From an analysis of amino acid sequences, it was found that the 36 kDa protein is a pro-CMCase 1 having an N-terminal residue, Ala, the 19th amino acid of the peptide deduced from the nucleotide sequence of CMC1 on the cDNA, and that the 34 kDa protein is a mature CMCase 1. Alteration of the cell morphology of S. cerevisiae was induced by transformation with YEp-plasmid carrying CMC1.