【摘要】 对比研究热处理(69～81℃)过程中牛初乳IgG分子抗原决定簇部位及其蛋白质G结合部位的变性动力学。利用单向琼脂扩散法(RID)监测IgG分子的热变性状况,其抗原决定簇部位热变性可用反应级数为1.2的方程较好地描述。结果表明,在69,72,77,81℃条件下IgG变性的D值分别为5000,2000,500,270 s,Z值为9.43℃,变性活化能为270.55 kJ/mol;利用蛋白质G亲和色谱法监测IgG分子上蛋白质G结合部位的热变性状况,在反应级数n=1.2,温度在69,72,77,81℃条件下IgG变性的D值分别为14286,3333,625,313 s,Z值为7.25℃,变性活化能为316.42 kJ/mol。所以IgG分子中抗原决定簇部位较之其蛋白质G结合部位更易于受热变性,较之RID,采用蛋白质G亲合色谱法检测牛初乳制品IgG的结果将偏高。更多还原

【Abstract】 Thermoresistance of the antigen determinant region and Protein G-binding region of bovine immunoglobulin G(IgG) were studied using Single Radial immunodiffusion(SRID) and Protein G affinity chromatography.The kinetic and thermodynamic parameters for heat-induced denaturation of IgG in colostrum matrix were determined over a temperature range of 69~81 ℃.The denaturation of the two IgG regions was both best described assuming an apparent reaction order of 1.2.D values,the time required to reduce the binding activities of IgG by 90%,were 5000,2000,500,270s for RID and 14286,3333,625,313 s for Protein G affinity chromatography at 69,72,77,81 ℃ respectively.Similarly,Z values,the degrees necessary to reduce the D value in one logarithmic cycle,were estimated to be 9.43℃ for SRID and 7.25℃ for Protein G affinity chromatography.The activation energy values of the denature reactions of the antigen determinant region and Protein G-binding region of bovine immunoglobulin G(IgG) were 270.55 and 316.42 kJ/mol respectively.So the antigen determinant region was more labile than Protein G-binding region of IgG,compared to RID,the quantitative results of IgG content in bovine colostrum containing products would be overestimated.更多还原