Purification and characterisation of intracellular alpha-galactosidases from Acinetobacter sp.

Two alpha-galactosidases (Ag-I & Ag-II) were purified from Acinetobacter sp. Both the enzymes were monomeric with pH optima of 7.0 and molecular weight of 65 kDa for Ag-I and 37 kDa for Ag-II. The temperature optima for Ag-I was between 50 and 60 degrees C and that of Ag-II was 40 degrees C. Both the enzymes were strongly inhibited by metal ions Ag2+ and Hg+, pCMB and SDS (1 %). The enzymes were found to be active on both natural and synthetic substrates. Artificial substrate, pNPGal, has shown more affinity to enzyme than natural substrate raffinose. The half-life (t(1/2)) of Ag-I varied from 1.85 h at 90 degrees C to 7.6 h at 70 degrees C.