Enzyme Assignment
By: Jazmynn McKay
Name: LCT (Lactase)
Structure, Function, and Genetics: Molecular Location on chromosome 2: The LCT gene is located on the long (q) arm of chromosome 2 at position 21. The substrate of lactase is molecular compound lactose.
Description: Lactase is primarily a digestive enzyme that is produced by specialized cells that line the lumen of the small intestine. Lactase 's primary function is to break down a sugar called lactose. Lactose is a sugar that is found in milk as well as many other dairy products. Since lactose is a very large sugar, it cannot be absorbed naturally by the human body. In order to metabolize this form of sugar, your body needs lactase to break down lactose into two smaller particles called glucose and galactose. These smaller sugar molecules are more easily absorbed by the cells in your intestine.
[pic]Fig 1 (Mcgrath, 2005)
Only lactose is broken down by lactase. Other sugars such as sucrose do not fit into the active site of lactase and therefore are not broken down.
Lactase deficiency: Some people are unable to produce enough lactase to meet their bodies ' needs. In some cases, the lactase enzyme is totally absent. These patients are said to be suffering from lactase deficiency, or more commonly known as; lactose intolerance. According to a service of the National Institutes of Health, symptoms of lactase deficiency begin 30 minutes to 2 hours after ingesting milk or a similar dairy product. Symptoms include bloating of the stomach, abdominal cramps, flatulence (gas), nausea and diarrhea. Larger doses of dairy products often cause more severe symptoms. Premature births, bowel surgery, intestinal diseases and intestinal infections are all possible risk factors for developing lactose intolerance. Fortunately, lactase supplements are available, for those that have lactose intolerance. The lactase in the capsule dissolves the sugar contained in the food and this permits your body to absorb
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