The Effect of Papain Preparations on Beef Skeletal Muscle Proteins a

SUMMARY The results reported here represent a preliminary study of the action of papain on the proteins of beef skeletal muscle. Suspensions of protein preparations which had been isolated from beef semitendinosus muscle were incubated with both crystalline papain and a commercial enzyme preparation. Analyses of ultrafiltrates of the enzyme digests indicated that all of the skeletal muscle protein fractions studied were affected by papain to some extent. Under the experimental conditions employed, the intracellular proteins were affected less by the commercial “meat tenderizer” than by crystalline papain. However, the effect of the two enzyme preparations on the connective tissue fractions was comparable. Papain appeared to affect mucoprotein and collagen more than the other skeletal muscle proteins. Incubation with papain markedly lowered the viscosity of the mucoprotein preparation. Collagen suspensions were converted to thick gels by the action of papain. These observations and the results of ultrafiltrate analyses suggest that the tenderizing effect of papain may be due at least in part to the breakdown of connective tissue.