Expression of human pancreatic secretory trypsin inhibitor in Saccharomyces cerevisiae

Abstract

Human pancreatic secretory trypsin inhibitor (PSTI) cDNA was expressed in Saccharomyces cerevisiae using the yeast acid phosphatase PHO5 promoter. The product encoded by the PSTI-coding cDNA was correctly processed in yeast cells, and the PSTI molecules were efficiently secreted into the medium. The amino acid composition and the N-terminal amino acid sequence of the secreted PSTI molecules were identical to those of the authentic PSTI polypeptides from human pancreas, and the product exhibited trypsin-inhibitory activity.