来源于青霉Penicillium sp. C6的β-1,3(4)-葡聚糖酶基因的克隆及酶学性质分析

从青霉Penicillium sp. C6菌株基因组DNA中克隆到一个新的16家族的葡聚糖酶基因，命名为bglc6(GenBank登录号:JX854434)。其cDNA全长为1 044 bp，包含N端前20个氨基酸的信号肽序列和一个16家族的结构催化域。bglc6编码的氨基酸序列与Grosmannia clavigera kw1407的假设葡聚糖酶蛋白序列最高一致性为64%。成熟蛋白BglC6在毕赤酵母中已成功表达，酶学性质分析表明，BglC6最适pH为4.5，最适温度为50℃，在酸性范围内具有良好的稳定性。以大麦葡聚糖酶为底物时，BglC6的比活、Km及Vmax值分别为253.8 U/mg，8.42 mg/mL，478.4 μmol/min·mg。蛋白BglC6对大多数金属离子有较好的抵抗能力。因此，该葡聚糖酶在动物饲料行业领域中具有潜在的应用前景。

Gene Cloning and Characterization of a β-1,3(4)-Glucanase from Penicillium sp. C6

Bglc6, a glycoside hydrolase with 16 families glucanase gene, was cloned from Penicillium sp. C6. The full-length of cDNA was 1 044 bp, including a putative signal peptide of 20 residues and a catalytic domain with glycosyl hydrolase of 16 families. The deduced amino acid sequence showed the highest identity (64%) with the putative endo-1,3(4)-β-glucanase from Grosmannia clavigera kw1407. The mature albumen BglC6 was successfully expressed in Pichia pastoris. The enzymatic characteristics analysis showed that the optimum pH and temperature for the recombinant glucanase BglC6 was pH 4.5 and 50℃. It exhibited good stability within acid pH range. When using barley β-glucan as substrate, the specific activity, Km and Vmax values were 253.8 U/mg, 8.42 mg/mL and 478.4 μmol/min·mg, respectively. BglC6 had better resistance to majority metal ions. Therefore, this glucanase possess potential application in animal feed industry.