Enzyme catheptic

There are four major proteolytic catheptic enzymes apparently associated with the lysosomal particles in muscle tissues (73, 74). These are ... 

Based on model studies with bovine spleen catheptic enzymes, West et al. (96) have suggested that cathepsins may be involved in the onset of rigor mortis by degrading the sarcoplasmic reticulum resulting in decreased binding capacity for Ca2 The free Ca2+ would then be free to initiate rigor mortis. 

In general, in beef muscle free catheptic activity reaches its maximum between four and six days postmortem (81, 92). At the same time major textural properties of meat show large changes between four and 13 days postmortem (33). Lysosomal enzymes have been implicated in the tenderization of meats by a number of workers. 

The activation and inactivation of enzymes has been of particular interest to food scientists. Knorr et al (1992) reported on the inactivation of polyphenol oxidase in real food systems in response to moderate temperatures and pressures. Ohmori et a/. (1991, 1992) showed that neutral and alkaline proteases are more sensitive than acid proteases in beef muscle. The rupture of lysosomal membranes, releasing catheptic proteases, occurs at 1—2 kBar pressure. In some cases, HHP can catalyze reactions such as the synthesis of oligosaccharides (Pelenc et al, 1992) and affect the activity of cellulases (Murao et al, 1992). 

Many protein systems betides those discussed have been subjected to oxidative studies. Some of these are carbonic anbydrase (52), papain, and catheptic-like enzymes (53-57), invertase (58), succinic dehydrogenase (59), triosephosphate dehydrogenase (60), glycerol oxidase (61), and scarlet fever toxin (62). 

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