Abstract: In order to investigate the effect of adding L-Lys on the phosphorylation of myofibrillar proteins from chicken thigh meat under high (3% NaCl) and low salt (1% NaCl) conditions, myofibrillar proteins were extracted from the salted chicken meat samples and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the phosphorylated myofibrillar proteins were identified by fluorescence staining and liquid chromatography-tandem mass spectrometry (LC-MS). The differences in the phosphorylation level of chicken myofibrillar proteins among different treatment groups were explored. The results showed that the phosphorylation level of myofibrillar proteins in the 1% NaCl + 0.06% L-Lys group was significantly lower than that of the 0% and 1% NaCl groups (P < 0.05), but did not significantly differ when compared with that of the 3% NaCl and 3% NaCl + 0.06% L-Lys groups (P > 0.05), showing that the addition of L-Lys reduced the phosphorylation level of myofibrillar proteins under low salt condition. The phosphorylation levels of α-actinin-2, β-enolase, tropomyosin α-1 chain, myosin light chain 2, and myosin light chain 3 in the 1% NaCl + 0.06% L-Lys group were significantly lower than those in the 1% NaCl group (P < 0.05). The phosphorylation levels of myosin heavy chain, M protein, β-enolase, myosin light chain 2, and myosin light chain 3 in the 1% NaCl + 0.06% L-Lys group were significantly lower than those in the 3% NaCl group (P < 0.05). The results of this study indicated that the addition of 0.06% L-Lys had an overall positive effect on the phosphorylation of myofibrillar proteins.

Key words: protein phosphorylation; sodium salt; L-lysine; meat quality