A negative correlation exists between calpastatin activity and meat tenderness. Therefore, it is important to determine the mechanism of calpastatin inactivation in postmortem skeletal muscle. Western immunoblot analysis was performed to determine the protease(s) responsible for degradation of muscle calpastatin during postmortem storage. To accomplish this, purified calpastatin was digested wi...

Calpain (Ca(2+)-dependent intracellular protease)-induced proteolysis has been considered to play a role in myoblast fusion to myotubes. We found previously that calpastatin (the endogenous inhibitor of calpain) diminishes transiently during myoblast differentiation. To gain information about the regulation of calpain and calpastatin in differentiating myoblasts, we evaluated the stability and ...

It is generally accepted that the Ca(2+)-dependent interaction of calpain with calpastatin is the most relevant mechanism involved in the regulation of Ca(2+)-induced proteolysis. We now report that a calpain-calpastatin association can occur also in the absence of Ca(2+) or at very low Ca(2+) concentrations, reflecting the physiological conditions under which calpain retains its inactive confo...

OBJECTIVE To test whether HLA-DR alleles influence the production of particular autoantibodies in rheumatoid arthritis (RA) patients, we screened synovial proteins with sera of RA patients homozygous for different HLA-DR alleles by using 2D blots. We found that sera of RA patients homozygous for HLA-DRB1*0404 recognised a 100-kDa synovial protein identified as calpastatin. We studied B and T ce...

To gain knowledge about the behaviour of calpastatin (the specific inhibitor of the Ca(2+)-dependent thiol protease calpain) in the intact cell, we analysed the inhibitor by specific antibodies and determined its activity in erythrocytes from individuals 20-34 years old (young) and 70-93 years old (old). Differences between old and young in the behaviour of erythrocyte calpastatin were observed...

Restriction fragment length polymorphisms (RFLP) have been identified at the bovine calpastatin locus. The objective of the present study was to determine whether these polymorphisms are related to variations in calpastatin activity or beef tenderness in unrelated animals of mixed breeding. A sample of 83 crossbred steers from sires representing eight different breeds was examined to determine ...

Localization of the two main components of the Ca(2+)-dependent proteolytic system has been investigated in human neuroblastoma LAN-5 cells. Using a monoclonal antibody which recognizes the N-terminal calpastatin domain, it has been shown that this inhibitory protein is almost completely confined in two granule-like structures not surrounded by membranes. Similar calpastatin distribution has be...

An immunological biosensor for calpastatin was developed on a surface plasmon resonance based system (Biacore Q). The performance of the biosensor assay was evaluated using ovine and bovine muscle and heart extracts with known calpastatin activity. In addition, the relationship between immunologically detectable calpastatin at 1 day postmortem and shear force at 14 days postmortem was investiga...

Restriction fragment length polymorphisms (RFLP) have been identified at the bovine calpastatin locus. The objective of the present study was to determine whether these polymorphisms are related to variations in calpastatin activity or beef tenderness in unrelated animals of mixed breeding. A sample of 83 crossbred steers from sires representing eight different breeds was examined to determine ...

Tenderness is a key component of palatability, which influences consumers’ perception of meat quality. There are a variety of factors that contribute to variations in tenderness, including postmortem proteolysis. A more complete understanding of this biological mechanism regulating tenderness is needed to ensure consistently tender beef. Numerous reports indicate μ-calpain is primarily responsi...