Carbohydrates

ID #1012

Several lectures ago we were discussing the breaking of disaccharides by the body and that it was as simple as an alpha linkage vs. a beta linkage to be able to digest Maltose vs. Cellobiose. Well I was wondering if it was the same concept for people who are lactose intolerant and if they are missing the ability to break the bond between glucose and galactose?


The answer, as with many questions in this class, is "yes...but." :)

Lactose intolerance is due to the inability to cleave the covalent bond between glucose and galactose. Since there is no mechanism in place to remove intact lactose from the intestines into the bloodstream (as there is for glucose, for example), the lactose stays in the intestines and is fair game (and a great food source) for the bacteria in your intestine, which ferment the sugar and produce gas as a byproduct.

Now here's the "but..." part. This inability to hydrolyze (digest) lactose doesn't specifically have anything to do with alpha or beta linkages. It's simply because that individual does not have sufficient lactase, the enzyme that catalyzes this hydrolysis reaction.

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