Abstract: The production of recombinant chymosin is disclosed in which an insoluble form of chymosin precursor is produced by a bacterial host cell transformed by a vector including a coding sequence for said precursor. Solubilization of said insoluble form of chymosin precursor is accomplished using urea at a concentration of at least 7M or guanidine hydrochloride at a concentration of at least 6M prior to cleaving said precursor to form chymosin. Said solubilization preferably additionally involves the denaturation of said precursor in an alkaline aqueous solution, e.g., at a pH between a 9 and 11.

Abstract: A synthetic gene characterised in that it codes for the expression of urogastrone or a sub-unit thereof is disclosed.The production thereof by the assembly and ligation of a number of nucleotide blocks is also disclosed, as are corresponding plasmid recombinants, transformed cells and the production thereof.The expression of urogastrone is further disclosed.Urogastrone is a polypeptide hormore (protein) which may be isolated in small amounts from human urine. It has an application in the treatment of ulcers and in the promotion of wound healing. The present invention provides a more viable commercial production.