Myosin heavy chain isoform and metabolic profile differ in beef steaks varying in tenderness

David S. Dang, Jared F. Buhler, Kara J. Thornton, Jerrad F. Legako, Sulaiman K. Matarneh

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Our objective was to investigate possible differences in muscle fiber characteristics of beef longissimus lumborum (LL) steaks varying in tenderness (very tender vs. intermediate tender). Therefore, the relative abundance of myosin heavy chain (MHC) isoforms and activity/abundance of several glycolytic and oxidative enzymes were compared between the two steak groups. Greater (P < 0.05) content of MHC type IIa (MHC-IIa) and activities of phosphofructokinase (PFK) and glycogen phosphorylase (GP) were observed in the very tender steaks. Conversely, intermediate tender steaks had greater (P < 0.05) contents of MHC type I (MHC-I) and succinate dehydrogenase (SDH) and greater citrate synthase (CS) activity. Increased tenderness in the very tender steaks was associated with greater (P < 0.05) proteolysis as evaluated by desmin and troponin-T degradation. Further, mitochondrial calcium uniporter (MCU) was lower (P < 0.05) in the very tender steaks than steaks of intermediate tenderness. Collectively, shifting muscle characteristics toward a more glycolytic type appears to positively impact postmortem proteolysis and tenderization.

Original languageEnglish
Article number108266
JournalMeat Science
StatePublished - Dec 2020


  • Fiber type characteristics
  • Mitochondria
  • Proteolysis
  • Tenderness


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