Hong Mi-Ri, Kim Yeong-Su, Joo Ah-Reum, Lee Jung-Kul, Kim Yeong-Suk, Oh Deok-Kun
Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Korea.
J Microbiol Biotechnol. 2009 Aug;19(8):818-22.
A beta-1,3-1,4-glucanase from the fungus Laetiporus sulphureus var. miniatus was purified as a single 26 kDa band by ammonium sulfate precipitation, HiTrap Q HP, and UNO Q ion-exchange chromatography, with a specific activity of 29 U/mg. The molecular mass of the native enzyme was 52 kDa as a dimer by gel filtration. beta-1,3-1,4-Glucanase showed optimum activity at pH 4.0 and 75 degrees . The half-lives of the enzyme at 70 degrees and 75 degrees were 152 h and 22 h, respectively. The enzyme showed the highest activity for barley beta- glucan as beta-1,3-1,4-glucan among the tested polysaccharides and p-nitrophenyl-beta-D-glycosides with a K(m) of 0.67 mg/ml, a k(cat) of 13.5 s(-1) and a k(cat)/K(m) of 20 mg/ml/s.
从真菌硫黄多孔菌微小变种中提取的一种β-1,3-1,4-葡聚糖酶，通过硫酸铵沉淀、HiTrap Q HP柱和UNO Q离子交换色谱法纯化，得到一条单一的26 kDa条带，比活性为29 U/mg。通过凝胶过滤法测得天然酶的分子量为52 kDa，呈二聚体形式。β-1,3-1,4-葡聚糖酶在pH 4.0和75℃时表现出最佳活性。该酶在70℃和75℃下的半衰期分别为152小时和22小时。在测试的多糖和对硝基苯基-β-D-糖苷中，该酶对大麦β-葡聚糖（作为β-1,3-1,4-葡聚糖）表现出最高活性，其米氏常数（K(m)）为0.67 mg/ml，催化常数（k(cat)）为13.5 s(-1)，催化效率（k(cat)/K(m)）为20 mg/ml/s。
