Some properties of beta-D-galactosidase from the adult filarial nematode Setaria digitata.

beta-D-galactosidase (beta-D-galactoside galactohydrolase, E.C. 3.2.1.23) activity was localised in the digestive tract of Setaria digitata. The enzyme extract shows maximum activity in the pH range between 3.5 and 5.0 and at 45 degrees C. The enzyme shows the Km value of 3.636 mM for the substrate 6-bromo-2-naphthyl beta-D-galactoside and Vmax of 28.57 nmol 6-bromo-2-naphthol liberated mg-1 protein min-1. Activation/inhibition of the enzyme by various ions, medicinal plants and drugs has been studied. Polyacrylamide gel electrophoresis revealed that the enzyme exists as single form. The medicinal plants and the drug filarin effectively inhibit the enzyme. The significance of these results are discussed in relation to chemotherapy.