Abstract A novel β-1,3-1,4-glucanase in the glycoside hydrolase family 5 (GH5) has been identified in the secretome of Paenibacillus polymyxa KF-1. The recombinant GH5 enzyme PpBglu5A shows broad substrate specificity, with strong lichenase activity, medium β-1,3-glucanase activity, and minimal cellulase activity. Barley β-glucan, lichenan, curdlan, and carboxymethyl cellulose are hydrolyzed to varying degrees by PpBglu5A, with the highest catalytic activity being observed with barley β-glucan. Hydrolysates from barley β-glucan or lichenan are primarily glucan oligosaccharides with degrees of polymerization from 2 to 4. PpBglu5A also hydrolyzes oat bran into oligosaccharides mainly consisted of di-, tri-, and tetra- oligosaccharides that are useful in the preparation of gluco-oligosaccharides. In addition to hydrolytic activity, transglycosylation was also observed with PpBglu5A and cellotriose as substrate. An in vitro assay indicated that the recombinant PpBglu5A has antifungal activity and can inhibit the growth of Canidia albicans. These results suggest that PpBglu5A exhibits unique properties and may be useful as an antifungal agent.

中文翻译：

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多粘类芽孢杆菌 KF-1 中葡聚糖的降解 GH5 β-1,3-1,4-葡聚糖酶 PpBglu5A

摘要 在多粘类芽孢杆菌 KF-1 的分泌组中发现了一种新的 β-1,3-1,4-葡聚糖酶，属于糖苷水解酶家族 5 (GH5)。重组GH5酶PpBglu5A显示出广泛的底物特异性，地衣酶活性强，β-1,3-葡聚糖酶活性中等，纤维素酶活性极低。大麦 β-葡聚糖、地衣多糖、凝胶多糖和羧甲基纤维素被 PpBglu5A 水解不同程度，其中大麦 β-葡聚糖的催化活性最高。来自大麦 β-葡聚糖或地衣聚糖的水解物主要是聚合度为 2 至 4 的葡聚糖寡糖。PpBglu5A 还可以将燕麦麸水解为主要由二、三和四寡糖组成的寡糖，可用于制备葡聚糖。寡糖。除了水解活性，用 PpBglu5A 和纤维三糖作为底物也观察到转糖基化。体外试验表明重组 PpBglu5A 具有抗真菌活性并能抑制白色念珠菌的生长。这些结果表明 PpBglu5A 表现出独特的特性，可用作抗真菌剂。