Yeast processing system

摘要

A polypeptide for production in yeast comprises a fusion of a signal peptide, a leader peptide and a heterologous protein or polypeptide. The polypeptide is modified in its amino acid sequence adjacent to a yeast processing site positioned between the C-terminal end of the leader peptide and the N-terminal end of the heterologous protein so as to provide a presentation of the processing site which makes it accessible to proteolytic cleavage. Such a presentation is provided by adding one or more amino acids (at least one of which is negatively charged) to either the C-terminal end of the leader or the N-terminal end of the protein, or both. The heterologous protein may, for instance, be aprotinin or insulin precursor or an analogue thereof.