Abstract

PURIFICATION AND CHARACTERIZATION OF Β-D-GLUCOSIDASE FROM THE DIGESTIVE TRACTS OF AN AFRICAN GIANT SNAIL (ACHATINA ACHATINA)

*Ozioko, Paul C. ;Ugwu, Okechukwu P. C. ; Chilaka, F.C. and Ude, Sylvester M.C.

Department of Biochemistry, University of Nigeria, Nsukka Enugu State, Nigeria.

ABSTRACT

Purification and characterization of β-D-glucosidase were studied from homogenates of the digestive tracts isolated from mature A. achatina. After centrifugation, the crude enzyme extracts were subjected to purification steps comprising 40% Ammonium Sulphate precipitation, dialysis and gel filtration column chromatography. Gel filtration on Sephadex G-200 Columns yielded a 100.71 purification fold. Also, the gel filtration yielded three prominent peaks, designated peaks A, B, and C, in the elution profile of the protein. Peak B had predominantly high β-glucosidase activities. The purified enzyme was characterized with respect to effects of pH, temperature and substrates affinities. The results showed that it had a pH and temperature optima of 4.5 and 50oC respectively. Kinetic parameters showed that the β-glucosidase component had a Vmax of 946.97μmole/min and a Km of 4.3mM cellobiose. This study shows that β-glucosidase subunit of cellulases from digestive tracts of A. achatina could be utilized for degradation of cellulose-containing materials because of the high yield and high substrate affinity when coupled with other cellulase subunits.

Keywords: Achatina achatina, β-glucosidase, Purifications, Characterization, and Cellobiose.