SECRETION OF MOUSE ALPHA-AMYLASE FROM FISSION YEAST SCHIZOSACCHAROMYCES-POMBE - PRESENCE OF CHYMOSTATIN-SENSITIVE PROTEASE ACTIVITY IN THE CULTURE-MEDIUM

We have constructed two secretion vectors for Schizosaccharomyces pomb e using an SV40 promoter and the secretion signals of the pGKL killer toxin complex derived from Kluyveromyces lactis. Although indigenous s ecretory glycoproteins tend to accumulate in the periplasmic space of S. pombe, we have succeeded in the secretion of mouse alpha-amylase in to the culture medium. The efficiency of secretion, processing pattern , stability and culture conditions for mouse alpha-amylase were studie d in S. pombe. The 128 kDa killer secretion signal was more effective in directing secretion of mouse alpha-amylase than the 28 kDa killer s ecretion signal. We detected a chymostatin-sensitive protease activity in the culture medium of S. pombe, which digests mouse alpha-amylase secreted into the culture medium. The addition of 5 mug/ml chymostatin was shown to protect mouse alpha-amylases from this degradation.