A comparative study of S-nitrosylated myofibrillar proteins between red, firm and non-exudative (RFN) and pale, soft and exudative (PSE) pork by iodoTMT-based proteomics assay.

• Myofibrillar protein of S-nitrosylation in pork longissimus thoracis was identified. • Differential SNO-modified proteins between PSE and RFN meat were analyzed. • S-nitrocysteines of myosin and actin were differentially detected in two meat groups. • Sarcomeric protein S-nitrosylation could be an alternative pathway of NO affecting meat quality. In this paper, the S-nitrosylated myofibrillar protein in pork was comparatively analyzed between pale, soft, and exudative (PSE) and red, firm, and non-exudative (RFN) meat. The S-nitrosothiol and immunoblot of S-nitrosylated protein indicated that the overall protein S-nitrosylation level in PSE pork was higher than that in RFN pork. Proteomics showed that 114 SNO-modified cysteines corresponding to 65 proteins were over-expressed in PSE samples while 74 nitrosylated cysteines of 20 proteins were over-expressed in RFN samples. Differential proteins including myosin, actin, actinin, nebulin, titin, troponin-I, and filamin were distributed in the cytoskeleton and muscle fibers, participating in muscle contraction, cell development, and myofibril assembly by exerting binding activity. The enriched KEGG pathways included tight junction, regulation of actin cytoskeleton, glycolysis/gluconeogenesis, AMPK signaling pathway, and HIF-1 signaling pathway. Our data suggest that S-nitrosylation of myofibrillar protein could be an alternative pathway of NO involved in the regulation of fresh meat quality. [ABSTRACT FROM AUTHOR]