Purification and Partial Characterization of a Novel β-1,3-Endoglucanase from Streptomyces rutgersensis

A β-1,3-endoglucanase produced by Streptomyces rutgersensis was purified to a homogeneity by the fractional precipitation with ammonium sulfate, ion exchange chromatography on Q-Sepharose and hydrophobic chromatography on Butyl Sepharose. A typical procedure provided 11.74-fold purification with 12.53 % yield. SDS-PAGE of the purified protein showed one protein band. The exact molecular mass of the enzyme obtained by mass spectrometry was 41.25 kDa; the isoelectric point was between pH 4.2–4.4. The optimal β-glucanase catalytic activity was at pH 7 and 50 °C. An enzyme was only active toward glucose polymers containing β-1,3 linkages and hydrolyzed Saccharomyces cerevisiae cell wall β-glucan in an endo-like way: reaction products were different molecular size β-glucans, which were larger than glucose.