Indirect assay of milk clotting activity of Mucor miehei proteinase (Fromase) in combined rennets

Abstract

SummaryMilk clotting activity of Mucor miehei proteinase (commercial name Fromase) was determined in combined rennets as the difference between the total activity of combined rennet and the residual activity after inhibition of Fromase by the purified immunoglobulin fraction of a Fromase antiserum. The proposed method is simple, rapid, and makes possible the use of any arbitrary method for assaying milk clotting activity. The application of the immunoglobulin fraction, instead of the whole antiserum, is necessary owing to the presence of nonspecific proteinase inhibitors in blood serum.