本研究旨在通过应用基于碘TMT的亚硝基蛋白质组学，用不同的处理方法（一氧化氮供体或一氧化氮合酶抑制剂）定量描述牛肉半膜（SM）中的S-亚硝基化。结果表明，在牛肉SM中368个蛋白中检测到2096个S-亚硝基化半胱氨酸位点。此外,筛选差异SNO修饰的蛋白质，其中一些涉及关键的生化途径，包括钙释放相关的蛋白质，能量代谢酶，肌原纤维，和细胞骨架蛋白。GO分析表明，差异蛋白位于广泛的细胞区室中，如细胞质，细胞器,和线粒体，为S-亚硝基化在死后肌肉中发挥广泛作用提供了先决条件。此外，KEGG分析验证了这些蛋白质参与了多种死后代谢过程的调节，尤其是糖酵解.最后，死后肌肉中S-亚硝基化水平的变化可能会影响关键肌肉蛋白的结构和功能，导致不同程度的肌肉代谢，最终影响牛肉品质。
This study aimed to quantitively profile the S-nitrosylation in beef semimembranosus (SM) with different treatments (nitric oxide donor or nitric oxide synthase inhibitor) by applying iodoTMT-based
nitrosoproteomics. Results showed that 2096 S-nitrosylated cysteine sites in 368 proteins were detected in beef SM. Besides, differential SNO-modified proteins were screened, some of which were involved in crucial biochemical pathways, including calcium-releasing-related proteins, energy metabolic enzymes, myofibrils, and cytoskeletal proteins. GO analysis indicated that differential proteins were localized in a wide range of cellular compartments, such as cytoplasm, organelle, and mitochondrion, providing a prerequisite for S-nitrosylation exerting broad roles in post-mortem muscles. Furthermore, KEGG analysis validated that these proteins participated in the regulation of diverse post-mortem metabolic processes, especially glycolysis. To conclude, changes of S-nitrosylation levels in post-mortem muscles could impact the structure and function of crucial muscle proteins, which lead to different levels of muscle metabolism and ultimately affect beef quality.
