里氏木霉一种未糖基化的低分子量1,4-β-葡聚糖-葡聚糖水解酶的特性分析
Characterization of an unglycosylated low molecular weight 1,4-beta-glucan-glucanohydrolase of Trichoderma reesei.
作者信息
Ulker A, Sprey B
机构信息
Institut für Biotechnologie der Kernforschungsanlage Jülich, F.R.G.
出版信息
FEMS Microbiol Lett. 1990 Jun 1;57(3):215-9. doi: 10.1111/j.1574-6968.1990.tb04232.x.
A low molecular weight endoglucanase (1,4-beta-glucan glucanohydrolase E.C.3.2.1.4) was purified to homogeneity by a two-step procedure from 7 day old culture filtrates of Trichoderma reesei. The endoglucanase was obtained by BioGel A 0.5 m gel chromatography followed by preparative PAGIF. The purified endoglucanase was homogeneous upon titration curve separation. Enzyme characteristics were: Mr 25 kDa, pI 7.5. The amino acid composition is predominantly neutral (mainly glycine). The N-terminus is arginine. The pH-optimum for this endoglucanase was 5.8 and its optimal temperature was at 52 degrees C. The activity of this endoglucanase gave a strong increase in CMC-fluidity with only a small release of reducing sugars. The endoglucanase was 0.2% of total culture medium protein content. The reducing sugars upon CMC digestion were G1-G4. The enzyme had no specificity towards crystalline cellulose (Avicel) or xylan. The endoglucanase is not a glycoprotein.
采用两步法从里氏木霉7日龄培养滤液中纯化出一种低分子量内切葡聚糖酶（1,4-β-葡聚糖葡聚糖水解酶，E.C.3.2.1.4），使其达到同质纯。该内切葡聚糖酶先经BioGel A 0.5m凝胶色谱，再经制备性聚丙烯酰胺凝胶等电聚焦（PAGIF）获得。纯化后的内切葡聚糖酶在滴定曲线分离时呈单一峰形。酶的特性为：分子量25 kDa，等电点7.5。氨基酸组成主要为中性氨基酸（主要是甘氨酸）。N端为精氨酸。该内切葡聚糖酶的最适pH为5.8，最适温度为52℃。该内切葡聚糖酶的活性使羧甲基纤维素（CMC）流动性大幅增加，而还原糖释放量很少。该内切葡聚糖酶占总培养基蛋白质含量的0.2%。CMC消化产生的还原糖为G1 - G4。该酶对结晶纤维素（微晶纤维素）或木聚糖无特异性。该内切葡聚糖酶不是糖蛋白。
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