Patent ID: 7501265

Claim:
A method for the preparation of a recombinant polypeptide comprising a) transforming a non-human host cell with an expression vector comprising: (1) a nucleic acid sequence capable of regulating transcription in a host cell, operatively linked to (2) a chimeric nucleic acid sequence that encodes a fusion protein, wherein said chimeric nucleic acid sequence comprises (a) a nucleic acid sequence encoding a full-length chymosin pro-peptide, linked in reading frame to (b) a nucleic acid sequence that is heterologous to the pro-peptide and that encodes the recombinant polypeptide, wherein the heterologous nucleic acid sequence is located immediately downstream of the nucleic acid sequence encoding the chymosin pro-peptide; operatively linked to (3) a nucleic acid sequence encoding a termination region that is functional in said host cell, b) growing the non-human host cell to produce said fusion protein, c) obtaining said fusion protein from said non-human host cell, and d) contacting said fusion protein with a mature form of an autocatalytically maturing aspartic protease that is capable of cleaving the chymosin pro-peptide, whereby said chymosin pro-peptide is cleaved from said fusion protein to release said recombinant polypeptide.