alpha-Galactosidase (alpha-D-galactoside galactohydrolase, EC 18.104.22.168) was purified (26-fold) from the germinating seeds of lentil (Lens culinaris) by affinity precipitation with alginate. The purified enzyme gave a single band corresponding to molecular-mass of 40 kDa on SDS-PAGE. The optimum temperature and pH of the enzyme were determined as 40 degrees C and 5.5, respectively. The enzyme was very stable at a temperature range of 4-65 degrees C and at a pH range of 4-7. The values of kinetic constants K-m and V-max using p-nitrophenyl-alpha-D-galactopyranoside (PNPG) as substrate were 0.191 mM and 0.73 U, respectively. Results suggest that affinity precipitation is an attractive process for the purification of alpha-galactosidase.