title: Myosin light chain 1 release from myofibrillar fraction during postmortem aging is a potential indicator of proteolysis and tenderness of beef.
abstract: The objective of this study was to identify proteins in bovine longissimus dorsi muscle that are related to tenderness. Two dimensional difference in gel electrophoresis (2D-DIGE) was used to compare the sarcoplasmic fractions from steaks that differed in star probe values at 14 days postmortem. The intensity of myosin light chain 1 (MLC1) was greater in the sarcoplasmic fraction prepared from steaks that had lower star probe values. It was hypothesized that μ-calpain catalyzes the release MLC1 into the sarcoplasmic fraction. Myofibrils from beef longissimus dorsi were purified and incubated with μ-calpain and the appropriate buffer controls. μ-Calpain was added at 1.23 μg (0.0875 U) of pure μ-calpain/mg myofibrillar protein. Incubations of one and 120 min had a greater abundance of MLC1 in the supernatants than the control incubations. As a consequence of μ-calpain proteolysis, MLC1 is rapidly released from the myofibril and is a potential indicator of proteolysis and improvement in beef tenderness.
authors: Department of Animal Science, Iowa State University, Ames, IA 50011 USA.
authors: M J
authors: MJ
authors: Anderson
authors: S M
authors: SM
authors: Lonergan
authors: E
authors: E
authors: Huff-Lonergan
mesh_terms: D000818:Animals; D002154:Calpain / Q000378:metabolism; D002417:Cattle; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D008460:Meat; D018482:Muscle, Skeletal / Q000737:chemistry; D009210:Myofibrils / Q000378:metabolism*; D018994:Myosin Light Chains / Q000378:metabolism*; D011180:Postmortem Changes; D059748:Proteolysis
chemical_list: D018994:Myosin Light Chains; D002154:Calpain; C449002:mu-calpain