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 CM-Sephadex 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 differentK _m and V_max values withp-nitrophenyl α-D-galactopyranoside, raffinose and melibiose as substrates and also differed in their thermal stabilities