FOOD SCIENCE ›› 2019, Vol. 40 ›› Issue (16): 1-7.doi: 10.7506/spkx1002-6630-20180926-279

• Food Chemistry •     Next Articles

Effect of Temperature and pH on Dephosphorylation of Myofibrillar Protein in Vitro

REN Chi, HOU Chengli, LI Xin, BAI Yuqiang, ZHANG Dequan   

  1. Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing 100193, China
  • Online:2019-08-25 Published:2019-08-26

Abstract: This study determined the effect of temperature (25, 15, and 4 ℃) and pH (5.2, 5.8, and 6.4) on dephosphorylation of myofibrillar protein, aiming to provide a theoretical basis for improving meat quality. Myofibrillar protein from postmortem muscle was extracted and alkaline phosphatase (AP) was added to catalyze its dephosphorylation. The phosphorylation level was detected by sodium dodecyl sulfate-polyacrymyl gel electrophoresis (SDS-PAGE) followed by sequential fluorescence staining of the gels using Pro-Q Diamond and SYPRO Ruby. Moreover, AP activity was measured by a commercial kit. The results demonstrated that at pH 5.8 and 6.4, the phosphorylation level of myofibrillar protein in the AP group significantly decreased with the prolongation of incubation (P < 0.05), while no significant change occurred at pH 5.2 (P > 0.05). Likewise, the control group showed no significant change in the phosphorylation level of myofibrillar protein throughout the incubation period (P > 0.05). At 4 ℃ and pH 5.2, AP activity was inhibited, delaying the catalytic time (P < 0.05). Interestingly, AP catalyzed not only the dephosphorylation of myofibrillar protein but also its own dephosphorylation, which caused no loss of activity. Increasing temperature and pH in a certain range could promote the dephosphorylation ability of AP, thereby decreasing the phosphorylation level of myofibrillar protein and making the reaction start earlier. These findings can be important for improving meat quality and provide a new idea for meat preservation.

Key words: protein phosphorylation, alkaline phosphatase, dephosphorylation, temperature, pH

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