Purification and Characterization of a Novel 尾-1,3鈥?,4-Glucanase (Lichenase) from Thermophilic Rhizomucor miehei with High Specific Activity and Its Gene Sequence
文摘
Production, purification, and characterization of a novel 尾-1,3鈥?,4-glucanase (lichenase) from thermophilic Rhizomucor miehei CAU432 were investigated. High-level extracellular 尾-1,3鈥?,4-glucanase production of 6230 U/mL was obtained when oat flour (3%, w/v) was used as a carbon source at 50 掳C. The crude enzyme was purified to homogeneity with a specific activity of 28818 U/mg. The molecular weight of purified enzyme was estimated to be 35.4 kDa and 33.7 kDa by SDS鈥揚AGE and gel filtration, respectively. The optimal pH and temperature of the enzyme were pH 5.5 and 60 掳C, respectively. The Km values of purified 尾-1,3鈥?,4-glucanase for barley 尾-glucan and lichenan were 2.0 mM and 1.4 mM, respectively. Furthermore, the gene (RmLic16A) encoding the 尾-1,3鈥?,4-glucanase was cloned and its deduced amino acid sequence showed the highest identity (50%) to characterized 尾-1,3鈥?,4-glucanase from Paecilomyces thermophila. The high-level production and biochemical properties of the enzyme enable its potential industrial applications.
Keywords:
characterization; gene cloning; purification; 尾-1,3鈭?,4-glucanase; Rhizomucor miehei