Influence of myosin heavy chain isoform expression and postmortem metabolism on the ATPase activity of muscle fibers

• Published in: Meat science 2004-12, Vol.68 (4), p.587-594
• Main Authors: Bowker, B.C, Botrel, C, Swartz, D.R, Grant, A.L, Gerrard, D.E
• Format: Article
• Language: English
• Subjects: adenosine triphosphate; adenosinetriphosphatase; ATPase activity; Biological and medical sciences; electrical treatment; enzyme activity; enzyme inhibition; Food industries; Fundamental and applied biological sciences. Psychology; glycolysis; immunohistochemistry; Meat and meat product industries; meat quality; muscle fibers; muscle protein; Myosin heavy chain isoform; myosin heavy chains; oxidative phosphorylation; pig carcasses; pork; Postmortem metabolism; protein degradation; rigor mortis; temperature
• ISSN: 0309-1740; 1873-4138
• DOI: 10.1016/j.meatsci.2004.05.010

The objective of this study was to determine the effects of postmortem muscle pH and temperature declines on the actomyosin ATPase activity of muscle fibers expressing different MyHC isoforms. Using a quantitative histochemical procedure to determine ATPase activity, the maximum actomyosin ATPase activity was determined on individual fibers classified by MyHC expression. Samples were collected from the red (RST) and white (WST) semitendinosus muscles at 3 min and 24 h postmortem from electrically stimulated (ES) and control (NS) pork carcasses. In samples taken at 3 min postmortem, type I fibers had the lowest ATPase activity staining and type 2X and 2B had the highest activity staining, with type 2A fibers intermediate. Postmortem time and carcass treatment did not influence the ATPase activity staining of type I muscle fibers. ATPase activity staining of 2A fibers was lower ( p