虎纹捕鸟蛛毒素Ⅰ中组氨酸残基的修饰与活性的关系

The Relationship Between Chemical Modification of Histidine of HWTX-Ⅰ and Bioactivity

用焦碳酸二乙酯 (DEPC)对虎纹捕鸟蛛毒素Ⅰ (HWTX Ⅰ )分子中的组氨酸残基进行了修饰 .修饰后的产物用高压液相色谱分离后采用质谱及氨基酸组成分析等相关技术进行鉴定 ,结果表明 ,DEPC对HWTX Ⅰ的修饰产生了咪唑环的单取代和咪唑环的双取代两种产物 .对修饰后的两种产物测定了对小鼠膈神经膈肌接头传递的影响 ,与天然的HWTX Ⅰ比较 ,组氨酸修饰后的HWTX Ⅰ其活性下降了 92 % ,证明组氨酸残基是HWTX

Huwentoxin\|Ⅰ(HWTX\|Ⅰ),a novel neurotoxin purified from the venom of the Chinese bird spider \%Selenocosmia huwena\%,were modified with groups\|specific reagent diethyl pyrocarbonate(DEPC).The modified toxin were isolated by high\|performance liquid chromatography and identified by the technology including mass spectrum and amino acid composition analysis,and comparison between the native and modified HWTX\|Ⅰ effect on isolated mouse neuromuscular transmission were carried out.The results indicate that the modification of the imidazole ring on His\|26 by DEPC result in monosubstituted and disubstituted derivative,both of them caused a drastic loss in activity to 8% of the native toxin.The data suggest that His\|26 is essential for the neurotoxicity.