Tasneem R, Prakash V
Food Chemistry Department, Central Food Technological Research Institute, Mysore, India.
J Protein Chem. 1989 Apr;8(2):251-61. doi: 10.1007/BF01024948.
alpha-Globulin, the high-molecular-weight protein fraction from Sesamum indicum L., was hydrolyzed to low-molecular-weight protein and peptides by pepsin, while its resistance to hydrolysis by group-specific enzymes, trypsin or alpha-chymotrypsin, was very high. The protein showed definite structural changes after proteolysis, especially after peptic hydrolysis, as evidenced from various biophysical data. The sedimentation velocity pattern of alpha-globulin hydrolyzed by trypsin or alpha-chymotrypsin indicated reduction in the percentage of 11S component, while the pepsin-hydrolyzed sample was devoid of any 11S component, indicating the absence of a native protein molecule. The fluorescence emission spectra of the various hydrolyzed alpha-globulin showed a red shift in the fluorescence emission maximum. The red shift was maximum with alpha-globulin hydrolyzed by pepsin and minimum with the trypsin-hydrolyzed sample. The far-ultraviolet-circular dichroic measurements indicated that most of the ordered structure of alpha-globulin was absent after pepsin hydrolysis, while after trypsin and chymotrypsin hydrolysis conformational changes were less.
芝麻（Sesamum indicum L.）中的高分子量蛋白质组分α-球蛋白被胃蛋白酶水解为低分子量蛋白质和肽，而其对组特异性酶（胰蛋白酶或α-胰凝乳蛋白酶）水解的抗性非常高。从各种生物物理数据可以看出，该蛋白质在蛋白水解后，尤其是在胃蛋白酶水解后，表现出明确的结构变化。经胰蛋白酶或α-胰凝乳蛋白酶水解的α-球蛋白的沉降速度模式表明11S组分的百分比降低，而经胃蛋白酶水解的样品中没有任何11S组分，这表明不存在天然蛋白质分子。各种水解后的α-球蛋白的荧光发射光谱显示荧光发射最大值出现红移。胃蛋白酶水解的α-球蛋白红移最大，胰蛋白酶水解的样品红移最小。远紫外圆二色性测量表明，胃蛋白酶水解后α-球蛋白的大部分有序结构消失，而胰蛋白酶和胰凝乳蛋白酶水解后构象变化较小。
