β-Glucosidase F42 of soy cotyledons was purified by ammonium sulfate fractionation, ion-exchange chromatography (CM-Sephadex-C-50, Sigma, St. Louis, MO) and gel filtration (Sephadex G-100, Sigma). The enzyme was purified 111.8-fold relative to its concentration in the crude extract. It had an apparent molecular mass of 53 kDa in gel filtration experiments and produced a 33-kDa band in sodium dodecyl sulfate–polyacrylamide gel electrophoresis, suggesting that it is dimeric. The purified β-glucosidase F42 was characterized as a glycoprotein after the identification of fucose, galactosamine and glucosamine by high-pressure anion-exchange chromatography–pulsed amperometric detector. Its highest activity was observed at pH 5.0 and 45C, and it was stable for up to 4 days at 25C. The Km of the enzyme was 0.12 mM p-nitrophenyl-β-d-glucopyranoside. β-Glucosidase F42 showed specificity for different substrates, and its activity was inhibited by 1 mM HgCl2, 10 mM glucono-δ-lactone or 150 mM glucose and increased by 10 mM MnCl2.