[Purification and some properties of Clostridium thermocellum endoglucanase, formed by a recombinant Escherichia coli strain].

The endoglucanase (EG5) has been isolated from the recombinant strain of E. coli TG1 carrying a plasmid with C. thermocellum F7 chromosomal DNA insertion. Using high performance ion-exchange chromatography and chromatofocusing, the enzyme was 98-fold purified with a 27% yield. The enzyme has a molecular mass of 35 kDa (SDS-PAGE data) and is represented by three isoforms with pI 4.4-4.8 (isoelectrofocusing data). The activity of EG5 was determined by chromatography on carboxymethylcellulose, amorphous cellulose, xylan, lichenan and avicel. The optimal conditions for these substrates hydrolysis are: pH 6.0-6.5, 80 degrees C (60 degrees C for avicel).