猪链球菌2型溶血素的化学修饰

用DTT、H2O2、DEPC、EDC、NAI、NBS、PCMB、2,3Diacetyl和SA 等9种化学修饰剂，处理猪链球菌2型江苏分离株提纯的溶血素，研究其分子中氨基酸侧链基团与其溶血活性的关系。结果表明，巯基、氨基、羧基和酪氨酸残基等与其溶血活性无关，而色氨酸、组氨酸和精氨酸的化学修饰引起溶血活性的大幅度下降，二硫键的化学修饰引起溶血活性的大幅度增强。显示色氨酸、组氨酸和精氨酸残基是该溶血素的活性必需基团，二硫键的断裂可引起其活性增强。

Chemical Modification of Streptococcus suis Type 2 Haemolysin

The haemolysin of Streptococcus suis type 2 Jiangsu isolate was purified. Effects of protein modification reagents on the haemolysin activity were detected. The haemolysin was not affected by PCMB, succinic anhydride(SA), EDC, and N-AI modification, and it indicated that sulfhudryl groups, amino groups, carboxyl groups and tyrosine residues were not essential to haemolysin activity. The haemolysin activity was significantly decreased after NBS, DEPC, 2,3-Diacetyl, H 2O 2 modification and was greatly increased after DTT modification.The results indicated that tryptophane residues, histidine residues, arginine residues and disulfides groups seemed to be essential to the haemolysin activity.