岩豆凝集素的纯化及其分子残基的化学修饰和活性关系

STUDY ON THE RELATION BETWEEN RESIDUE MODIFICATION AND BIOLOGICAL ACTIVITY OF MILLETTIA DIELSIANA HARMS. LECTIN

岩豆种子经侵取、硫酸铵分级、ＤＥＡＥ－纤维素离子交换和ＳｅｐｈａｄｅｘＧ－１００分子筛层析，获得ＦＰＬＣ上单一的凝集素样品，对此纯化的凝集素样品用Ｎ－溴代丁二酰亚胺、Ｎ－乙基顺丁烯二酰亚胺、二流苏糖醇，碘乙酸和对氯汞苯甲酸修饰其分子内的色氨酸和巯基．经计算，该凝集素分子内含有４个色氨酸和２４个流基，当色氨酸被修饰后其凝集活性全部丧失，而巯基被修饰后对其凝血活性无任何影响，表明巯基与凝集素分子的凝血活性无关，而色氨酸则是凝集活性所必需的基团．

Millettia dielsiana Harms. Lectin (MDL)was purified from the seeds of Millettia dielsiana Harmesx Diels by extraction, fraction with (NH4 )2SO4, DEAE-Cellulose ion-exchange chromatography and followed by gel filtration of Sephadex G- 100. The purified MDL showed single protein peak on FPLC,mwhfication disulfide groups(-SH)and Tryptophan(Trp)in MDL. The result showed that MDL did not need the -SH to deep its activity,but Trp was essential for MDL to keep activity. There were 4 Trp and 24 -SH in MDL molecules.