title: Postmortem proteolysis in three muscles from growing and mature beef cattle.
abstract: The objective of this study was to determine calpain system activity and postmortem protein degradation in three muscles from growing (n=6, 7.3 ± 0.5 months) and mature (n=6, 106.7 ± 43.1 months) beef cattle. The ratio of μ-calpain:total calpastatin activity tended to be lower in mature animals (P=0.08), suggesting reduced potential for proteolysis. Additionally, muscles from the mature group had greater calpastatin activity compared to calves at 6 days postmortem and had less μ-calpain autolysis and troponin-T and titin degradation during the aging period (P<0.01). Between the longissimus, semimembranosus, and triceps brachii muscles, the triceps brachii had the least postmortem proteolysis, with greater calpastatin activity and less troponin-T and titin degradation compared to other muscles (P<0.01). These data suggest that calpastatin activity in muscle from older animals is more persistent postmortem. This difference may contribute to the decreased protein degradation and increased toughness of beef from mature cattle, even after aging.
authors.affiliation: Department of Animal Science, Iowa State University, Ames, IA 50011, USA. Electronic address: scruzen@iastate.edu.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Cruzen
authors.forename: Pedro V R
authors.initials: PV
authors.lastname: Paulino
authors.forename: Steven M
authors.initials: SM
authors.lastname: Lonergan
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Huff-Lonergan
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000378:metabolism; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry*; D011180:Postmortem Changes; D059748:Proteolysis; D020107:Troponin T / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D020107:Troponin T; C033668:calpastatin; D002154:Calpain; C449002:mu-calpain
keywords: Beef; Calpain; Calpastatin; Postmortem proteolysis