Lactase carbohydrate digestion

Final digestion of dietary carbohydrates and proteins occurs on the lumen face of small intestinal enterocytes by so-caUed brush border enzymes , including maltase, sucrose, lactase and peptidases. 

The intestinal oligo- and disaccharidases are fixed components of the cell membrane of the brush border region of the wall of the small intestine. These enzymes digest dietary carbohydrate to monosaccharides which are absorbed through the intestinal wall. They include sucrase, maltase, isomaltase, lactase, trehalase, and hetero-p-glucosidase. In the late 1970s, it was realized that inhibition of all or some of these activities could regulate the absorption of carbohydrate, and that these inhibitors could... 

The enzyme lactase binds the carbohydrate lactose (C12H22O11) in its active site in Step [1]. Lactose then reacts with water to break a bond and form two simpler sugars, galactose and glucose, in Step [2]. This process is the first step in digesting lactose, the principal carbohydrate in milk. 

Intestinal processes studied with C02 breath tests are carbohydrate (lactose and starch) digestion (lactase and a-amylase activity), lipid digestion (lipase activity), protein digestion (trypsin activity), sugar absorption, fatty acid absorption, small intestinal bacterial overgrowth, oro-cecal transit time. The substrates used are indicated in Table 6. 

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