Protein changes in post mortem large yellow croaker (Pseudosciaena crocea) monitored by SDS-PAGE and proteome analysis

This study was devoted to the identification of proteins and specific peptides which could be used as indicators of freshness and quality in fish. The post mortem evolution of protein patterns in large yellow croaker muscle was monitored by SDS-PAGE and two-dimensional electrophoresis (2-DE) after cold storage for 0, 5, 10, 15, 20, 25 days. SDS-electrophoresis revealed the gradual degradation of protein bands of 16–17 kDa, 22–23 kDa, 35–36 kDa, 76–78 kDa, as well as the increase of protein bands of 32–34 kDa and 67 kDa. The analysis of 2-DE showed that five spots of interest, including 3 structural proteins, namely myosin heavy chain (MHC), LIM domain-binding protein 3 (LDB3) and troponin T, as well as 2 metabolic proteins α-enolase and glyceraldehyde 3-phosphate dehydrogenase, changed progressively, which could be used as the potential freshness markers of large yellow croaker. Further research is required to evaluate their expression and post mortem evolution in another fish species.