腌制过程钠离子抑制环腺苷酸依赖蛋白激酶活性机理

环腺苷酸依赖蛋白激酶通过调控原料肉关键蛋白质（酶）磷酸化水平，影响肌肉持水性、凝胶特性进而影响肉腌制品质。申请人研究发现，钠离子抑制环腺苷酸依赖蛋白激酶活性进而保持肉品质，但具体机理尚不清楚。本项目以环腺苷酸依赖蛋白激酶活性显著差异的原料肉为试验材料，采用肌肉原位模型鉴定不同钠离子强度下环腺苷酸依赖蛋白激酶活性消长规律；构建原位和离体模型，确证特定钠离子强度下cAMP、ATP的稳定性及其与环腺苷酸依赖蛋白激酶的结合能力；调节催化底物、cAMP和ATP浓度，分析钠离子条件下环腺苷酸依赖蛋白激酶活性变化；采用分子对接和模拟手段，解析钠离子对环腺苷酸依赖蛋白激酶构象及调节亚基cAMP结合域、催化亚基螺杆结构域的作用；纯化环腺苷酸依赖蛋白激酶，确证钠离子对α-螺旋、β-折叠、分子间作用力及关键结构域的影响，揭示钠离子抑制环腺苷酸依赖蛋白激酶活性机理，为丰富和发展肉品腌制机理提供新的理论参考。

Cyclic adenosine monophosphate dependent protein kinase （PKA）activity contributes significantly to meat quality in the salting, influencing water holding capacity, gel property by catalytic phosphorylation for key proteins or enzymes. Recently, we found that PKA activity was inhibited by sodium ion and then retain meat quality in the salting, but the inhibition mechanism is not well understanding. Therefore, the project will focus on the muscle with different PKA activity, to explore the activity of PKA under different sodium ion in situ model, to study the stability and binding capacity with PKA for cyclic adenosine monophosphate and adenosine triphosphate in situ and vitro when undergone the sodium ion, to verify the PKA activity in sodium ion stress by the addition with different concentration of catalytic protein substrate, cyclic adenosine monophosphate and adenosine triphosphate. Furthermore, the influence of high sodium ionic strength on the conformation of cyclic adenosine monophosphate binding domain for regulatory subunit and lobe subdomain of catalytic subunit, by molecular docking and simulation analysis. Meanwhile, the α-helix, β-sheet, molecular interactions and potential domain will be verified by vitro model. The mechanism of inhibition mechanism of cyclic adenosine monophosphate dependent protein kinase activity under sodium ion in the salting for fresh meat will be brought to lighter, to provide a theoretical reference for the development of meat preserving and salting technology.