title: Caspase 3 is not likely involved in the postmortem tenderization of beef muscle.
abstract: Postmortem proteolysis is an important determinant of beef tenderness. Caspase 3 is a protease that functions in apoptosis and has been shown to degrade myofibrillar proteins. Our objective was to evaluate whether caspase 3 activity is related to beef tenderness and muscle growth, and whether caspase 3 is activated in postmortem beef muscle. In experiment 1, longissimus thoracis (LT) and sternomandibularis muscle samples were obtained at 0, 0.25, 1, 3, 24, 72, and 240 h postmortem from 5 steers. In experiment 2, a group of 40 beef cattle was slaughtered at the University of Wyoming Meat Lab with 10 steers of different tenderness and growth characteristics chosen for the analysis of caspase 3 activity in the LT. In experiment 3, 10 steers with different tenderness but matched growth characteristics were chosen for analyses. In experiment 1, no significant activation (P = 0.70) of caspase 3 activity was detected; only a decreased activity at 72 (P = 0.05) and 240 h (P = 0.02) postmortem was observed. Western blot analysis of both muscle samples showed only the pro-caspase 3 form and failed to detect the activated enzyme. In experiment 2, caspase 3 activity in the LT immediately postmortem was greater (P = 0.05) for the cattle with increased Warner-Bratzler shear force values. No difference in caspase 3 activity was detected for experiment 3. Our results demonstrate that caspase 3 activity is not activated, with its activity decreasing with time postmortem, and caspase 3 activity is not associated with Warner-Bratzler shear force at slaughter. Therefore, caspase 3 is not anticipated to be involved in postmortem tenderization of beef.
authors.affiliation: Department of Animal Science, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Underwood
authors.forename: W J
authors.initials: WJ
authors.lastname: Means
authors.forename: M
authors.initials: M
authors.lastname: Du
mesh_terms: D000821:Animal Feed; D000818:Animals; D053148:Caspase 3 / Q000378:metabolism*; D002417:Cattle / Q000378:metabolism*; D003258:Consumer Behavior; D006801:Humans; D008297:Male; D008460:Meat / Q000592:standards*; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011180:Postmortem Changes; D011237:Predictive Value of Tests; D033081:Shear Strength; D013997:Time Factors
chemical_list: D010447:Peptide Hydrolases; D053148:Caspase 3