Flavobacterium johnsoniae昆布多糖酶的分离纯化及其催化性质

Purification and catalytic properties of a laminarinase from Flavobacterium johnsoniae

摘要:

约氏黄杆菌Flavobacterium johnsoniae具有分泌裂解酵母细胞壁酶系的能力, 经初步分析发现其发酵液中具有葡聚糖酶、几丁质酶和蛋白酶等活性。通过离子交换层析、疏水层析和凝胶过滤层析, 从该菌发酵液中分离纯化到一种昆布多糖酶。该酶分子量为35 kD左右, 其最适反应温度为50 °C, 最适反应pH为5.0。以昆布多糖和昆布寡糖为底物的反应表明, 该酶以内切酶作用模式进行催化水解。

关键词:约氏黄杆菌, 葡聚糖, 酵母细胞壁, 昆布多糖酶, 纯化

Abstract:

Flavobacterium johnsoniae is capable of secreting enzymes which can efficiently hydrolyze yeast cell wall. Preliminary analysis revealed the presence of glucanase, chintinase and protease activities in its culture supernatant. A laminarinase was purified from the extracellular components of F. johnsoniae through several isolation steps including ion exchange, hydrophobic interaction and gel exclusion chromatography. The molecular weight of the purified laminarinase is about 35 kD. The optimum temperature and pH of its catalyzed hydrolysis are 50 °C and 5.0, respectively. Laminarin and laminari-oligosaccharide were hydrolyzed by this laminarinase in an endoglucanase mode with laminaritriose as the main product.

Key words:Flavobacterium johnsoniae, Glucan, Cell wall of yeast, Laminarinase, Purification