Purification and characterization of a novel β-1,3/1,4-glucanase from Sistotrema brinkmannii HQ717718

Abstract

A highly efficient extracellular β-1,3/1,4-glucanase was purified from the culture broth of Sistotrema brinkmannii HQ717718. The molecular mass of β-1,3/1,4-glucanase was respectively determined to be 83 and 166 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography, indicating that the enzyme is a dimer. The optimum activity of β-1,3/1,4-glucanase against Avicel was observed at pH 4.0 and 65°C. Under the same conditions, Vmax, Km, and kcat values for Avicel were 136.5 U · mg-1 of protein, 3.8 mM, and 211 s-1, respectively. Furthermore, the DNA sequence of gene coding the enzyme showed a significant homology with hydrolases from the glycoside hydrolase family 55. Although β-1,3/1,4-glucanases have been purified and characterized from several other sources, S. brinkmannii β-1,3/1,4-glucanase is distinct from other β-1,3/1,4-glucanases due to its high catalytic efficiency toward Avicel and broad substrate specificity. © 2013 The Korean Society for Applied Biological Chemistry.