beta-Glucosidase catalyzes the sequential breakdown of cyanogenic glycosides in cyanogenic plants. The beta-glucosidase from Prunus armeniaca L. was purified to 8-fold, and 20% yield was obtained, with a specific activity of 281 U/mg protein. The enzyme showed maximum activity in 0.15 M sodium citrate buffer, pH 6, at 35 degrees C with p-nitrophenylglucopyranoside as substrate. The beta-glucosidase from wild apricot was used successfully for the saccharification of cellobiose into D-glucose. This enzyme has a V-max of 131.6 mu mol min(-1) mg(-1) protein, Km of 0.158 mM, K-cat of 144.8 s(-1), K-cat/K-m of 917.4 mM(-1) s(-1), and K-m/V-max of 0.0012 mM min mg mu mole(-1), using cellobiose as substrate. The half-life, deactivation rate coefficient, and activation energy of this beta-glucosidase were 12.76 h, 1.509 x 10(-5) s(-1), and 37.55 kJ/mol, respectively. These results showed that P. armeniaca is a potential source of beta-glucosidase, with high-affinity and catalytic capability for the saccharification of cellulosic material.