Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 10(1): 461 - 470. Published October 2008.
Purification and characterisation of two beta-glucosidases from termite workers Macrotermes bellicosus (Termitidae: Macrotermitinae)
Siaka BINATE, Denis N’DRI, Marie TOKA and Lucien Patrice KOUAME*
*Laboratoire de Biochimie et Technologie des Aliments de l’Université d’Abobo-Adjamé (Abidjan, Côte d’Ivoire), 22 BP 1297 Abidjan 22, Côte d’Ivoire.
Corresponding author e–mail:kouame_patrice@yahoo.fr
ABSTRACT
Objectives: The objective was to purify and characterise beta-glucosidases from termite Macrotermes bellicosus workers for use in glycobiotechnology and elucidate the role played by these enzymes in the degradation of plant material.
Methodology and results: Two beta-glucosidases were purified by a three-step procedure consisting of ion-exchange, size-exclusion and hydrophobic interaction chromatography techniques. Beta-Glc A and B had molecular weights estimated at 204 and 216 kDa, respectively, by SDS-PAGE; and 209 and 230 kDa, respectively, by gel filtration. Both enzymes exhibited the same temperature and pH optima for p-nitrophenyl-beta-D-glucopyranoside hydrolysis and were stable at 37°C. The enzymes showed a high specificity for the beta-glucosyl residue and preferred glucose-beta-(1-4) linkages to beta-(1-3), beta-(1-2) and beta-(1-6) linkages. Both beta-glucosidases were inhibited by sulfhydryl-binding reagents.
Conclusions and application of findings: The enzymes isolated in this study appear to be distinct from other known beta-glucosidases in terms of substrate specificity and low KM value for cellobiose. The physiological role of the two beta-glucosidases in the digestive tract of the termite could be the digestion of di-and oligosaccharides derived from celluloses. The enzymes could be used as a tool in the structural analysis of D-glucose containing oligosaccharide chains of glycoproteins, glycolipids and cellulose.
FULL PAPER [PDF AVAILABLE HERE]
