What is the function of brush border enzymes maltase, sucrase, and lactase?

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The essential idea is that these enzymes finish carbohydrate digestion right at the surface of the intestinal lining so monosaccharides can be absorbed. Maltase, sucrase, and lactase are disaccharidases on the microvilli of enterocytes in the small intestine. They hydrolyze the bonds in the three common disaccharides—maltose, sucrose, and lactose—to produce monosaccharides: maltase splits maltose into two glucose molecules; sucrase splits sucrose into glucose and fructose; lactase splits lactose into glucose and galactose. Monosaccharides are then ready to be taken up by the intestinal cells and into the bloodstream. This step distinguishes disaccharides from absorption-capable monosaccharides, which is why the function is to break disaccharides into monosaccharides. Lipids would be digested by lipases, and proteins by proteases, while polysaccharides are handled earlier by other enzymes. If lactase is deficient, lactose isn’t broken down and can cause osmotic and fermentative effects in the gut.