Sucrase-isomaltase

Sucrase-Isomaltase

Active site of sucrase-isomaltase.

Sucrase-isomaltase is an important enzyme complex located in the small intestine that plays a crucial role in the digestion of carbohydrates. It is responsible for the hydrolysis of sucrose and isomaltose, breaking them down into simpler sugars that can be absorbed by the body.

Structure

Sucrase-isomaltase is a glycoprotein composed of two subunits: sucrase and isomaltase. These subunits are linked together and anchored to the brush border membrane of the intestinal epithelial cells. The enzyme complex is synthesized as a single polypeptide chain that is later cleaved into the two functional subunits.

Function

The primary function of sucrase-isomaltase is to catalyze the breakdown of disaccharides into monosaccharides. Sucrase specifically hydrolyzes sucrose into glucose and fructose, while isomaltase breaks down isomaltose and other alpha-limit dextrins into glucose. This enzymatic activity is essential for the proper digestion and absorption of dietary carbohydrates.

Clinical Significance

Deficiency in sucrase-isomaltase activity can lead to a condition known as sucrase-isomaltase deficiency, which results in the malabsorption of sucrose and isomaltose. This can cause symptoms such as diarrhea, abdominal pain, and bloating after the ingestion of sucrose-containing foods. Diagnosis is typically made through a combination of clinical evaluation, dietary history, and enzymatic assays.

Related Pages

• Carbohydrate digestion
• Enzyme
• Small intestine
• Glycoprotein