Phosphorproteome Changes of Myofibrillar Proteins at Early Post-mortem Time in Relation to Pork Quality As Affected by Season

The
effect of season on phosphorylation of myofibrillar proteins
and meat quality of pork longissimus muscles was
investigated. Muscle samples were obtained from 40 pork carcasses
(10 for each season) at 45 min and 3 and 9 h post-mortem. Myofibrillar
proteins were extracted, separated by SDS-PAGE, quantified by phosphor-specific
staining, and finally identified by LC-MS/MS. Muscle pH, glycogen,
and ATP were measured, and pale, soft, and exudative (PSE) meat was
identified by pH value at 45 min post-mortem. A total of 23 bands
were detected on SDS-PAGE gels. The phosphorylation levels of bands
did not differ between PSE and normal meat. However, the phosphorylation
levels of 22 bands were significantly changed by season. Nine of them
showed different changes from 45 min to 9 h post-mortem, which were
identified to be involved in energy metabolism and sarcomere contraction.
Correlation analysis indicated the regulatory progress of these proteins
during rigor mortis. These observations contribute to a better understanding
of the biochemical processes for the conversion of muscle to meat
varying with season.

本研究探讨了季节对猪背最长肌肌原纤维蛋白磷酸化水平及肉品质的影响。共采集40头生猪胴体的肌肉样本，按季节分为4组（每组10头），分别于宰后45 min、3 h及9 h三个时间点采样。通过提取肌原纤维蛋白，采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）进行分离，以磷酸化特异性染色法完成定量，最终借助液相色谱-串联质谱（LC-MS/MS）鉴定蛋白。测定了肌肉pH值、糖原含量及三磷酸腺苷（ATP）水平，并以宰后45 min的pH值为指标，鉴定出苍白柔软渗出性（PSE）肉与正常肉。SDS-PAGE凝胶共检测到23个蛋白条带。各条带的磷酸化水平在PSE肉与正常肉间无显著差异，但其中22个条带的磷酸化水平受季节影响发生显著变化。其中9个条带的磷酸化水平在宰后45 min至9 h期间呈现独特变化趋势，经鉴定对应蛋白参与能量代谢与肌节收缩过程。相关性分析揭示了这些蛋白在尸僵过程中的调控进程。本研究结果有助于更深入理解随季节变化的肌肉向肉类转化的生化机制。