大豆胰蛋白酶抑制剂对鲢丝氨酸蛋白酶的作用

The inhibitory effect of soybean trypsin inhibitor on an endogenous serine proteinase of silver carp,Hypophthalmichthy molitrix

摘要:

研究了大豆胰蛋白酶抑制剂(STI)对鲢肌肉中肌原纤维结合型丝氨酸蛋白酶(MBSP)引起的肌原纤维蛋白降解作用的影响.大豆胰蛋白酶抑制剂经高度纯化后加入肌原纤维中以判断它对MBSP的抑制效果.在不添加STI的情况下,55 ℃加热30 min即可观察到肌球蛋白重链的分解,延长加热时间则可检测到肌动蛋白及原肌球蛋白的降解.相反,在终浓度为0.75 μg?mL-1的STI存在下,包括肌球蛋白重链在内的肌原纤维蛋白降解均能得到有效抑制,表明STI是MBSP的特异性抑制剂.由于肌球蛋白重链及肌动蛋白的完整性是构成鱼糜制品凝胶强度的主要因素,因此,STI的添加有可能提高鲢鱼糜制品的凝胶强度.

Abstract:

The effect of soybean trypsin inhibitor （STI） on the degradation of silver carp myofibrillar proteins caused by an endogenous myofibril-bound serine proteinase （MBSP） was studied. Soybean trypsin inhibitor was purified to homogeneity and added to myofibril to investigate its effect on preventing myofibrillar protein degradation. In the absence of STI, incubation at 55℃ for 30 min caused the degradation of myosin heavy chain. The degradation of actin and tropomyosin could also be detected after prolonged incubation. Compared with control, in the presence of STI, with final concentration of 0.75μg?mL^-1, proteolysis of myofibrillar proteins was greatly suppressed, the result showed that STI was an effective inhibitor in preventing degradation caused by MBSP. As the integrity of myosin heavy chain （MHC） and actin was the most important factor forming the elasticity of surimi, this result suggested the possibility that STI is applicable in surimi production in order to enhance the elasticity that is the quality of the final products.