Castanospermine: a potent inhibitor of sucrase from the human enterocyte‐like cell line Caco‐2

Abstract

The addition of castanospermine (5–50 μM) to a culture medium of Caco-2 cells results in a specific suppression of sucrase activity without modification of the biosynthesis of the enzyme. This effect is due to a direct inhibiting effect of castanospermine on Caco-2 sucrase activity. This inhibition is time-dependent (half-maximum efficiency at 10 min for 100 nM), enhanced by preincubation (suggesting a strong interaction with the enzyme), dose-dependent (ED₅₀ at 4 nM after 1 h preincubation period) and of the fully non-competitive type. The calculated K _i (2.6 nM) suggests that castanospermine is the most potent inhibitor of sucrase so far reported.