Expression of Aspergillus oryzae alpha-amylase gene in Saccharomyces cerevisiae

A fragment containing the full length cDNA from Aspergillus oryzae alpha-amylase has been amplified by PCR using specific synthetic oligonucleotides. The amplified cDNA was designed to favour its expression in yeast by modifying its upstream untranslated region. It was subcloned in the expression vector pYEX alpha 1, placed under the control of the yeast CYC1-GAL10 promoter and used to transform Saccharomyces cerevisiae. Cells were then able to express and secrete active alpha-amylase to the medium in a regulated fashion. The recombinant enzyme had similar electrophoretic mobility and catalytic properties to the original A. oryzae alpha-amylase.