PROCESS FOR THE PRODUCTION OF CHYMOSIN

摘要

A PROCESS FOR THE PREPARATION OF CHYMOSIN There is described a process for the preparation of chymosin in which an insoluble form of a chymosin precursor, such as methionine-chymosin, is produced by a host organism, such as Saccharomyces cerevisiae or E.coli, transformed with a vector including a gene coding for the chymosin precursor, wherein the insoluble form of the chymosin precursor is solubilised to produce a soluble native form of the chymosin precursor prior to cleaving the soluble native form of the chymosin precursor to produce chymosin. The solubilisation involves denaturing the insoluble chymosin precursor and then allowing it to renature forming the normal or native form of the chymosin precursor. The native form may then be cleaved to form chymosin. The denaturants used include aqueous solutions of urea or guanidine hydrochloride and alkaline solutions of pH between pH 9.5 and pH 11.5 either separately or in combination. In a particular type of colubilisation described, the insoluble chymosin precursor is denatured using a urea or guanidine hydrochloride solution. The resulting solution is then diluted into an alkaline solution to yield the native form of the chymosin precursor.