Abstract: Polypeptides that are cleared from the kidney and do not contain in their original form a Fc region of an IgG are altered so as to comprise a salvage receptor binding epitope of an Fc region of an IgG and thereby have increased circulatory half-life.

Abstract: Enzyme-catalyzed synthetic reactions having otherwise unfavorable equilibria are facilitated by recovery of polypeptides by electrodialysis. A process of preparing polypeptides is provided that can be operated continuously to produce high yields of enriched polypeptides without recourse to post-synthetic product manipulations heretofore employed that are expensive and present a risk of residual toxic by-products. The invention is applied to advantage in the preparation of alpha-L-aspartyl-L-phenylalanine lower alkyl esters.

Abstract: Cheese is prepared using rennin obtained from insoluble refractile bodies of a recombinant microbial host cell. The rennin is obtained by rupturing the recombinant hose cell, isolating and solubilizing the insoluble refractile bodies, and recovering active rennin. Recombinant techniques involve preparing cDNA corresponding to the coding sequence for calf rennin, introducing into an expression vector and expressing in a host cell. As much as 200 mg rennin per liter of culture may be recovered. Prorennin or preprorennin may be produced and rennin derived therefrom.