title: Purification and characterization of two endoglucanases from Melanocarpus sp. MTCC 3922.
abstract: This study reports the purification and characterization of endoglucanases (EG I and EG II) from a newly isolated thermophilic fungus, Melanocarpus sp. MTCC 3922. The molecular weight of EG I and EG II as with SDS-PAGE and pI were approximately 40 and 50 kDa, and approximately 4.0 and 3.6, respectively. EG I and EG II were optimally active at 50 and 70 degrees C, and pH 6.0 and 5.0, respectively. EG I was active over a broad range of pH (5.0-7.0), whereas, loss of activity was observed as the temperature was increased from 50 to 80 degrees C. However, EG II was active over pH 4.0-6.0 and temperature 40-80 degrees C. The presence of mercaptoethanol and SDS inhibited the EG I activity but showed no negative effect on EG II. Both the endoglucanases showed higher activity against barley-beta-glucan as compared to CMC. Km values of EG I and EG II for barley-beta-glucan were lower than CMC. Turn over number (K(cat)) and catalytic efficiency (K(cat)/Km) values of both the endoglucanases were higher with barley-beta-glucan as substrate than CMC. EG I showed affinity for Avicel indicating the presence of cellulose binding domains (CBD) whereas, EG II was found to lack CBD.
authors.affiliation: Department of Microbiology, Guru Nanak Dev University, Amritsar 143 005, India.
authors.forename: Jatinder
authors.initials: J
authors.lastname: Kaur
authors.forename: Bhupinder S
authors.initials: BS
authors.lastname: Chadha
authors.forename: Badhan A
authors.initials: BA
authors.lastname: Kumar
authors.forename: Harvinder S
authors.initials: HS
authors.lastname: Saini
mesh_terms: D001203:Ascomycota / Q000201:enzymology*; D044602:Cellulases / Q000378:metabolism*; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals; D013696:Temperature
chemical_list: D005656:Fungal Proteins; D008670:Metals; D044602:Cellulases