Inhibition of protease activity 2. Degradation of myofibrillar proteins, myofibril examination and determination of free calcium levels

摘要: The structure of muscle injected with specific cysteine protease inhibitors was examined to determine whether cause denaturation and the degradation post-mortem myofibrillar proteins followed using SDS electrophoresis. Given central role calcium in theories tenderisation level free measured during early period. enzyme inhibitor E-64 into m. longissimus et thoracis lumborum (LTL) on right side 12 lamb carcasses within 15 min death another Z-Phe-Ala-CHN(2). left LTL (control) saline (0.25 M NaCl). Muscle samples were obtained at death, pH 6.2 6.0 then 1 2 days (n=215). selected from eight portions (1-day post-mortem, six different carcasses) for examination by transmission electron microscopy. Matching light images myofibrils after determination fragmentation. Free concentration determined all (n=191) an ion selective electrode excluding those 'at death'. Light treated showed normal striations no evidence or aggregation compared control samples. This also applied processed Appearance 30-kDa subunit increased time (P<0.001) post-mortem. interaction between ageing stimulation had effect amount a protein designated M1. M1 pre-rigor greater stimulated muscle, but rate decline through day Proteolysis very rapid first 24 h ovine muscle. Ageing concentration, which as aged. As covariate (P< 0.05). Based non-linear model when reached plateau (∼110 μM) predicted 5.5 (ultimate). From qualitative observation levels there is support view that bind sarcomere proteins, occupying sites might bind. do not provide m-calpain has tenderisation, suggest along results activation μ-calpain likely occur before drops 6.2-6.1.