内切葡聚糖苷水解酶的分离纯化和内源荧光性质

利用离子交换和分子筛层析技术从拟康氏木霉Ｓ－３８固态发酵液中提纯了两个内切葡聚糖苷酶组分．测定了一个组分的内源荧光性质，结果表明：该酶分子的内源荧光几乎都来自色氨酸．Ｎ－溴代琥珀酰亚胺（ＮＢＳ）修饰导致了酶活力的完全丧失，但是酶荧光残留了２５％，抑制剂纤维二糖与酶结合可使部分酶荧光得到保护，同时这种结合也可以保护一定的色氨酸荧光不被外来淬灭剂淬灭．

Purification and Intrinsic Fluorescence Properties of Endoglucanases from Trichoderma pseudokiningii S 38

Two endoglucanases(EG Ⅰ,Ⅱ)from Trichoderma pseudokiningii S 38 were purified by DEAE Sephadex A 50,DEAE Sephadex A 25 and Sephadex G 100 chromatography.The molecular mass of purified enzymes estimated by SDS PAGE were 69 000 for EG Ⅰ and 60 000 for EG Ⅱ, respectively. Substrate specificity study indicated that both enzymes were endoglucanases. Spectroscopic data indicated that the fluorescence of EGⅠ comes from tryptophan residues in the enzyme. Complete inactivation of the NBS treated enzyme occurs well before the loss of fluorescence.The quenching studies with acrylamide suggested the occurrence of both collosional as well as static quenching process. The binding of cellobiose,a mechanism inhibitor,resulted in a decreasing in quenching efficiency.