利用酪蛋白酸钠的分子伴侣特性抑制蛋清蛋白的热聚集研究

Chaperone Property of Sodium Caseinate Prevents Thermal Aggregation of Egg White Proteins

酪蛋白酸钠的分子伴侣作用尚未在蛋清蛋白体系的热聚集研究中应用。通过测定溶液的浊度、上清液总蛋白含量、粒径分布以及分子质量分布变化,研究酪蛋白酸钠添加量对蛋清蛋白热聚集的影响。当酪蛋白酸钠质量浓度为2 mg/mL时可以抑制热处理(90℃,30 min)蛋清蛋白溶液(5 mg/mL)的热聚集,且随着酪蛋白酸钠添加量的增加(2~3 mg/mL),其抑制程度增加;当酪蛋白酸钠质量浓度较高时(4~5 mg/mL),由于酪蛋白酸钠的溶解性较低,抑制效果无显著变化(P<0.05)。还原SDS-PAGE电泳结果表明,酪蛋白酸钠对蛋清蛋白中的卵白蛋白、卵转铁蛋白热聚集的抑制效果决定了其对蛋清蛋白热聚集抑制效果。随着酪蛋白酸钠添加量的增加,热处理蛋清蛋白溶液中的不溶性聚集逐渐转变为可溶性聚集,结构紧密且体积较大的热聚集体转变为结构疏松体积较小的聚集体。研究结果表明,酪蛋白酸钠的添加可以抑制蛋清蛋白的热聚集。

The chaperone property of sodium caseinate has not been applied to prevent the thermal aggregation of egg white proteins.The effect of sodium caseinate on thermal aggregation of egg white proteins was analyzed via measuring the turbidity,soluble protein content of supernatant,particle size and molecular weight distribution.When the concentration of sodium caseinate was 2 mg/mL,the thermal aggregation(90℃,30 min)of egg white proteins solution(5 mg/mL)could be suppressed.And with the increasing of the addition of sodium caseinate(2-3 mg/mL),the inhibitory effect was enhanced.Due to the low solubility of sodium caseinate,the inhibitory effect of the aggregation was not significant changed at higher concentration of sodium caseinate(4-5 mg/mL).The results of SDS-PAGE illustrated that the inhibitory effect of sodium caseinate on the thermal aggregation of ovalbumin and ovaltransferrin determined its effect on preventing thermal aggregation the egg white proteins.With the increase of the addition of sodium caseinate,the insoluble aggregates of egg white proteins was gradually changed to soluble aggregates,and the large and dense aggregates were transformed to small and loose.The results indicated that sodium caseinate could prevent the thermal aggregation of egg white proteins.