Purification and Enzymatic Properties of a Difunctional Glycoside Hydrolase from HML366.

In the study, an extracellular enzyme HML CBH1 was purified from the fermentation solution of HML366, and characterized by biological and molecular analysis. Following the culturing of HML366 under the optimized conditions for enzyme production, an enzyme named HML CBH1 with a molecular weight of 48 kDa was purified using 3000 Da cellulose ultrafiltration column and anion exchange chromatography. The specific activity of the purified enzyme was 9.65 U/mg, and the optimum temperature and pH for the enzyme were 50 and 5.0 °C, respectively. The enzyme was stable at temperatures below 60 °C and pH ranging from 3.0 to 10.0. The partial amino acid sequence of HML CBH1 was analyzed by time-of-flight mass spectrometry, and Mascot and Blast analysis showed that the HML CBH1 sequence was identical to the protein gi:22138643, belonging to the glycoside hydrolase family 7, and had exoglucanase and endoglucanase activity.