α-苦瓜子蛋白和β-苦瓜子蛋白紫外光谱的研究  

THE STUDIES ON ULTRAVIOLET SPECTROSCOPY OFα-momocharin ANDβ-momocharin

作　　者：陈世芝[1] 徐薇[1] 王耀萍[1] 董贻诚 

机构地区：[1]中国科学院生物物理研究所

出　　处：《生物物理学报》1995年第1期16-20,共5页Acta Biophysica Sinica

摘　　要：对α－ｍｍｃ及β－ｍｍｃ进行了溶剂微扰差光谱的研究及在不同温度条件下的光谱滴定，结合最新得到的α－ｍｍｃ的晶体结构进行了分析和讨论，并与天花粉蛋白的紫外光谱进行了比较。The environment of tyrosine residues in α-momocharin (α-mmc) and β-momocharin (β-mmc) has been investigated by solvent perturbation differencr spectroscopy. Serveral perturbants with different molecular dimensions were used in pH range of 8.6 to 2.5. The results show that approximately 40%-50% of the twelve phenolic groups are 'exposed' and the rest are 'buried' in the interior of α-mmc and β-mmc. The effect of the various perturbants with different molecular dimensions at each pH value, except for D2O at pH8.6 are almost the same.Spectrophotometric titration has been carried out at 25℃, 40℃ for α-mmc, and 25℃, 35℃ for β-mmc. The titration curves of this two proteins have been shown to be of three steps. The first step take place at pH below 11.5,it is reversibe; The second step around pH 11.5- 12.0 at 25℃ and 11.0-11.5 at 40℃ for α-mmc and 35℃ for β-mmc,respectively. At pH above 12, the titration curve has a third step, suggesting that this two protein molecules have a rether stable core.Discussion has been made in relation to the crystal structure of a-mmc and the ultraviolet spectrocopy of TCS studied by our group recently.

关 键 词：α苦瓜子蛋白 β苦瓜子蛋白 紫外光谱 

分 类 号：Q71[生物学—分子生物学] Q510.1