Myofibrin-bound serine proteinase (MBP) and its degradation of myofibrillar proteins

Proteolysis of a myofibril-bound serine proteinase (MBP) from carp Cyprinus carpio on myofibrillar proteins and their gel formation ability were inves tigated, MBP readily decomposed myosin heavy chain as indicated by SDS-PAGE , In the preparation of kamaboko, the gel formation ability was diminished by addition of MBP, The optimum degradation temperatures of MBP to myosin h eavy chain in myofibril and kamaboko gel were 55 degrees C and 60 degrees C , respectively. The degradation effects of MBP on actin, alpha-actinin and tropomyosin were studied by the immunoblotting method. Because of its myofi bril-bound and myofibrillar protein degradation characteristics, MBP was re garded as the proteinase most probably involved in the modori effect.