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野花生豆凝集素(CML)经SephadexG-200测得分子量为103.OkD.用对二甲基氨基苯甲醛(DAB)为显色剂,测得每个CML分子含有5.9个色氨酸残基.在pH5.1,含8mol/L脲的醋酸缓冲液中,N-溴代丁二酰亚胺(NBS)可修饰CML分子中的5.6个色氨酸(Trp)残基,同时使CML的凝血活性完全丧失.用焦碳酸二乙酯(DEPC)和N-乙酰顺丁烯酰胺(NEM)分别修饰CML的组氨酸残基和半胱氨酸巯基后,CML的活性均无变化.CML在天然状态下荧光发射峰位于336nm处,用CML的专一性抑制糖N-乙酰半乳糖胺研究色氨酸的微环境,发现N-乙酰半乳糖胺可以淬灭CML中88%的色氨酸残基萤光,Stern-Volmer常数K=1.73L/mol.同时发现N-乙酰半乳糖胺能够保护CML,避免NBS对CML的修饰作用,表明色氨酸可能是CML维待活性所必需,并直接参与和专一性抑制糖的结合,其微环境较为疏水.
Wild Peanut Lectin (CML) has a molecular weight of 103 measured by Sephadex G-200. OkD. With p-dimethylaminobenzaldehyde (DAB) as a chromogenic reagent, each CML molecule was found to contain 5.9 tryptophan residues. N-bromosuccinimide (NBS) modified 5.6 tryptophan (Trp) residues in CML molecules in pH5.1, 8 mol / L urea-containing acetate buffer, and CML The complete loss of coagulation activity. No change was observed in the activity of CML after modifying histidine residues and cysteine thiol groups with diethyl pyrocarbonate (DEPC) and N-acetyl maleimide (NEM). CML in the natural state fluorescence emission peak located at 336nm, CML with specific inhibition of sugar N-acetylgalactosamine tryptophan microenvironment and found N-acetylgalactosamine can quench CML 88% of the color Amino acid residue fluorescence, Stern-Volmer constant K = 1.73 L / mol. At the same time, it was found that N-acetylgalactosamine can protect CML and avoid the modification effect of NBS on CML, indicating that tryptophan may be necessary for the maintenance of CML and directly participate in and specifically inhibit the binding of sugar, and its microenvironment is relatively hydrophobic .