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

Summary 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 .