α-Galactosidase from germinating guar (Cyamopsis tetragonolobus) seeds.

ABSTRACT

The changes in α-galactosidase activity in guar (Cyamopsis tetragonolobus) seeds was followed during seven days of germination. The enzyme activity was maximal on the first day of germination and gradually decreased during subsequent days. On the second day of germination the partially purified enzyme upon ion-exchange chromatography on CMSephadex C-50 was resolved into α-galactosidase-A (anionic), α-galactosidase-C1 (cationic) and α-galactosidase-C2 (cationic) and their relative proportions were 28,12 and 60%, respectively. The combined α-galactosidase C1 and C2 activities increased in the first two days of germination followed by significant decrease after the 3rd day onwards, whereas α- galactosidase-A remained fairly constant throughout the germination period, α- Galactosidase-A and C2 had different Km and Vmax values with p-nitrophenyl α-Dgalactopyranoside, raffinose and melibiose as substrates and also differed in their thermal stabilities.