Phosphorylation of myosin regulatory light chain affects actomyosin dissociation and myosin degradation

This research aimed to investigate the influence of myosin regulatory light chain (MRLC) phosphorylation on actomyosin dissociation and myosin degradation in post-mortem ovine longissimus thoracis (LT) muscle with a purpose for strategies to improve meat quality in practice. Data obtained show that the highest actomyosin dissociation occurred at 48 h post-mortem. Based on the cluster analysis of the actomyosin dissociation degree at 48 h post-mortem, samples were divided into high, middle and low-actomyosin dissociation groups. During 0.5-72 h post-mortem, the phosphorylation level of MRLC significantly decreased (P < 0.05), while actomyosin dissociation, and degradation of MRLC and myosin heavy chains (MHC) significantly increased (P < 0.05). The level of MRLC phosphorylation was negatively correlated with the degree of actomyosin dissociation (r = -0.794, P < 0.05), and the degradation of MRLC (r = -0.764, P < 0.05) and MHC (r = -0.826, P < 0.05). In conclusion, phosphorylation of MRLC may regulate actomyosin dissociation, as well as degradation of MRLC and MHC.