摘要
应用NBS ,WRK ,DTNB ,PMSF ,Phenylgloxalhydrate,DEPC等化学修饰剂对嗜热真菌所产的耐热木聚糖酶进行了化学修饰。分别作用于色氨酸残基和谷氨酸 (或天冬氨酸 )残基的NBS和WRK可使耐热木聚糖酶活性显著降低 ,而其他几种修饰剂无明显作用。木聚糖对NBS的修饰有抑制作用 ,3 0mg·mL-1的桦木木聚糖底物可完全阻止NBS对耐热木聚糖酶的修饰作用 ,但木聚糖底物不能阻止WRK对耐热木聚糖酶的失活作用。实验结果表明 ,色氨酸残基和谷氨酸 (或天冬氨酸 )残基位于酶的活性中心 ,且色氨酸残基位于酶的底物结合中心 ,而谷氨酸(或天冬氨酸 )残基可能位于酶的催化中心。
The modification chemicals of NBS, WRK, DTNB,PMSF,Phenylgloxal hydrate,DEPC were used to react with a thermostable xylanase from Thermomyces lanuginosus . The thermostable xylanase could be inactivated by NBS (N bromosuccinmide) and WRK (N ethyl 5 phenylisoxazolium 3 sulfonate). The tryptophan residues and glutamate/aspartate residues might be involved in the active site of the enzyme. Chemical modification of the xylanase with NBS and WRK revealed that trytophan and glutamate/aspartate were essential for the activity. 3 0?mg·mL -1 birchwood xylan could completely inhibit the inactivation of xylanase by NBS. The substrate had no effect on the modification by WRK. The results revealed that tryptophan was in the substrate binding site and glutamate/aspartate in the catalytic site.
出处
《中国农业大学学报》
CAS
CSCD
北大核心
2004年第4期4-9,共6页
Journal of China Agricultural University
基金
教育部研究重点项目
国家"十五"攻关课题( 2 0 0 1BA70 8B0 4 0 6 )
关键词
嗜热真菌
耐热木聚糖酶
化学修饰
活性中心
Thermomyces lanuginosus
thermostable xylanase
chemical modification
active site
