Abstract
The present paper describes the effects of pressure and post-mortem aging treatments on in situ proteasome activity in rabbit and bovine skeletal muscles. Synthetic peptide hydrolyzing activity of rabbit proteasomes remained in the muscle after exposure to pressures up to 100 MPa. However, when a pressure of 400 MPa or more was applied, proteasomes were markedly inactivated. The extraction of proteasomes from excessively pressurized muscle appeared to be difficult. Proteasomes in aged muscle remained relatively stable throughout the aging process, with activity after 168 h (7 days) being 35%, 48%, 53% and 31% of the 0 h post-mortem LLVY, LSTR, AAF and LLE total hydrolyzing activities, respectively. The synthetic peptide hydrolyzing activities of bovine muscle proteasomes were similar to those of rabbit skeletal muscle proteasomes. The results suggest that synthetic peptide hydrolyzing activity remains in muscle exposed to relatively low pressures. Furthermore, it is known that high-pressure treatment induces fragmentation of myofibrils, modification of actin-myosin interaction and activation of intramuscular proteinases, cathepsins and calpains. Thus, proteasomes are probably involved in the tenderization process in combination with other intramuscular proteinases under high-pressure conditions. Our findings confirmed that proteasomes play a role in meat tenderization induced by high-pressure treatment or aging.
Highlights
The present paper describes the effects of pressure and post-mortem aging treatments on in situ proteasome activity in rabbit and bovine skeletal muscles
According to Mykles and Harie (1995), proteasomes have proteasome activity is stimulated by mild denaturing at least five activities - peptidylglutamyl peptide hydrolase treatments
We describe the effects of pressure and postmortem aging treatments on in situ proteasome activity of rabbit and bovine skeletal muscles
Summary
The present paper describes the effects of pressure and post-mortem aging treatments on in situ proteasome activity in rabbit and bovine skeletal muscles. The proteasome or multicatalytic proteinase complex various chemicals and treatments, such as polylysine (MCP) was first isolated from bovine pituitaries (Orlowski (Tanaka et al, 1986; Mellgren, 1990), SDS (Wilk and and Wilk, 1981). This enzyme is a high-molecular-mass Orlowski, 1983; Dahlmann et al, 1985; Tanaka et al, 1986; intracellular proteinase (20S proteasome; 700 kDa) that has Otsuka et al, 1998; Yamamoto et al, 2005a), fatty acids a complex subunit composition and multicatalytic (Wilk and Orlowski, 1983), heat treatment (Mykles, 1989a; proteolytic activities with different specificities (Rivett, Mykles, 1989b; Koohmaraie, 1992; Otsuka et al, 1998; 1989a, 1989b, 1993; Orlowski, 1990). According to Mykles and Harie (1995), proteasomes have proteasome activity is stimulated by mild denaturing at least five activities - peptidylglutamyl peptide hydrolase treatments
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