Rat small-intestinal galactosidases. Separation by ion-exchange chromatography and gel filtration

Abstract

1. The chromatography of rat small-intestinal β-galactosidase activities on gel-filtration and ion-exchange columns has been studied. Five different substrates were used to measure β-galactosidase activity (lactose, phenyl β-galactoside, o-nitrophenyl β-galactoside, p-nitrophenyl β-galactoside and 6-bromo-2-naphthyl β-galactoside) and the activity was measured at one acid and one more neutral pH value. 2. By gel filtration one acid β-galactosidase, hydrolysing lactose and the hetero-β-galactosides at about the same rate, and one more neutral β-galactosidase, hydrolysing lactose much more rapidly than the hetero-β-galactosides, were separated. 3. By ion-exchange chromatography the acid enzyme was fractionated into two components. These may be individual enzymes or different forms of the same enzyme.