Inhibition of β-galactosidases with mono- and disaccharides

Abstract

It was demonstrated that, in reactions of the hydrolysis of model substrate 2-nitrophenyl-β-D-galactopyranoside (2-NPGP) monosaccharides D-fructose and D-xylose with hydroxyl substituents oppositely directed at the neighboring carbon atoms in the furan ring, as in D-glucose, act as noncompetitive inhibitors of β-galactosidase from E. coli; for mushroom, β-galactosidases from P. canescens and A. oryzae D-galactose is a stronger inhibitor. It was also found that the inhibition constant is the highest in the case of the most active enzyme (E. coli) and is the lowest for the least active one (P. canescens).