食品与发酵工业2017，Vol.43Issue(9)：64-70,7.DOI:10.13995/j.cnki.11-1802/ts.014028
3种离子强度下pH值对罗非鱼肌球蛋白溶解度及分子构象的影响
Effect of pH on tilapia myosin solubility and conformation under three ionic strength solutions
摘要
Abstract
Effect of various pH (2.0-12.0) on solubility of tilapia myosin and surface hydrophobicity,SDSPAGE and α-helix contents of tilapia myosin were investigated at three ionic strength levels.Results showed that,in the experimental range,with increasing of ionic strength,the isoelectric point of myosin was shifted to acidic pH.In low ionic strength (1 mmol/L KCl),physiological ionic strength (150 mmol/L KCl) and high ionic strength (600 mmol/L KCl) solution,the pH of the minimum solubilities of myosin was 5.5,5.0 and 4.5 respectively.At extreme acid (pH 2.0) and alkali (pH 11.0-12.0) condition,the solubility of myosin was higher than 80％.Under the neutral and high ionic strength,surface hydrophobicity was low and α-helix content was high and stability of myosin was good.During acid-induced refolding process,lower surface hydrophobicity was observed near the isoelectric point,and surface hydrophobicity increased under the acid condition of deviating from the isoelectric point.However,unfolded myosin might refold partly under extreme acidic conditions,and molecular degradation and electrostatic interactions could lead to the high solubility.During alkali-induced refolding process,the surface hydrophobicity increased with the rising of pH value,the macro-molecular polymer was formed through disulfide bonding between myosin heavy chains.In neutral pH condition,alkaline and extreme acidic conditions,α-helix content increased with the increase of salt concentration,and therefore high salt could protect the secondary structure of myosin.All above results indicated that myosin molecule could be unfolded to an intermediate sate similar to "molten globule" at extreme alkali and high salt condition.关键词
罗非鱼肌球蛋白/pH值/离子强度/去折叠/溶解度/构象Key words
tilapia myosin/pH/ionic strength/unfolding/solubility/conformation引用本文复制引用
付苇娅,周春霞,朱潘红,郑惠娜,洪鹏志,杨萍..3种离子强度下pH值对罗非鱼肌球蛋白溶解度及分子构象的影响[J].食品与发酵工业,2017,43(9):64-70,7.基金项目
国家自然科学基金项目(31201389) （31201389）
广东省教育厅科技创新项目(2013KJCX0098) （2013KJCX0098）
广东省省部产学研合作专项(2013A090100009) （2013A090100009）
