蛋白质浓度、pH值、离子强度对兔骨骼肌肌球蛋白热凝胶特性的影响

Effects of Protein Concentration,pH Value and Ionic Strength on Heat-induced Gel Properties of Myosin from Rabbit Skeletal Muscle

研究了蛋白质浓度、pH值、离子强度对肌球蛋白凝胶硬度和保水性的影响。结果显示:凝胶硬度和保水性随蛋白质浓度增大而显著增高(P<0 05);腰大肌(Psoasmajor,PM)和半膜肌(Semimembranosusproprius,SMp)肌球蛋白凝胶(0 6mol/LKCl),分别在pH值为6 0和5 5时硬度最高,且两者均在pH值为6 0时保水性最大;凝胶硬度(pH6 0)随离子强度增大而升高,最佳条件为1 0mol/LKCl(PM)和0 6mol/LKCl(SMp),最佳保水性条件均为1 0mol/LKCl。扫描电镜显示,PM和SMp蛋白在0 2mol/LKCl中均呈现丝状三维网络结构,具有粗和长的丝,而在0 6mol/LKCl中则为球状颗粒凝聚交联形成的网络,具有更好的多孔性;凝胶在蛋白等电点(pH<6 0)形成粗糙的结构,多孔性较差,而pH值在6 0附近形成均匀细致的网络,pH值更高时,凝胶结构则变得粗糙且多孔性下降。

Effects of myosin concentration,pH value and ionic strength on heat-induced gel hardness and water holding capacity(WHC) were studied.The results showed gel hardness and WHC increased significantly with the increase of myosin concentration (P<0.05).The psoas major (PM) gel and semimembranosus proprius (SMp) gel were the hardest at pH 6.0 and 5.5,respectively,and both of their WHC were the best at pH 6.0.At pH 6.0,the hardness of both gels increased with the increase of ionic strength and had the peak at 1.0 mol/L and 0.6 mol/L KCl,respectively.The WHC of both gels was the best at 1.0 mol/L KCl.The structures of both gels through scanning electronic microscope showed three dimensional network with long and thick filament at 0.2 mol/L KCl and granular aggregates with better porosity at 0.6 mol/L KCl.The structures were rough with worse porosity at isoelectric point (pH<6.0) of myosin and had uniform porosity at pH 6.0.The inhomogeneous aggregates would exist throughout the gels if pH value became higher.