赖氨酸诱导低离子强度下罗非鱼肌球蛋白增溶及机制

L-Lysine-Induced Solubilization and Mechanism of Tilapia Myosin under Low Ionic Strength Conditions

以罗非鱼肉为原料提取肌球蛋白,研究5 mmol/L赖氨酸对低离子强度(1~150 mmol/L KCl)条件下肌球蛋白(蛋白质量浓度为2.0 mg/m L)体系浊度、溶解度及分子结构和形态的影响,分析赖氨酸诱导肌球蛋白增溶机理。结果表明,在低离子强度下,肌球蛋白分子聚集成纤丝,溶解度低,赖氨酸的添加能显著降低肌球蛋白体系的浊度(P<0.05),抑制蛋白分子间的聚集,增溶效果明显,增溶后分子的表面疏水性增大,α-螺旋含量减小(P<0.05),且与酸碱处理组比较,在1~40 mmol/L KCl范围内,赖氨酸增溶效果更好。增溶后的肌球蛋白Zeta-电位的绝对值增大,丝状体解离。

Myosin was extracted from tilapia muscle, and the effect of 5 mmol/L L-lysine on the turbidity, solubility, molecular structure and shape of myosin（2.0 mg/mL） was studied in low ionic strength（0–150 mmol/L KCl） solutions. The L-lysine-induced solubilization behavior and mechanism of myosin were analyzed. Results showed that myosin molecules were assembled into filaments with low solubility under low ionic strength conditions. L-Lysine could significantly decrease the turbidity of myosin dispersion（P 0.05）, and inhibit the aggregation of protein molecules, thereby having an obvious solubilizing effect on L-lysine. Surface hydrophobicity of soluble myosin was increased, and α-helix content was decreased（P 0.05）. Compared with the p H shifting group, the solubilization of myosin by L-lysine was more remarkable in 1–40 mmol/L KCl solution. The absolute zeta potential of myosin treated with L-lysine was increased, leading to the dissociation of myosin filaments.