Maltase-glucoamylase

Maltase-glucoamylase (also known as MGAM) is an enzyme that plays a crucial role in the digestion of starch in the human body. It is encoded by the MGAM gene in humans. This enzyme is a member of the glycoside hydrolase family 31, which includes several related enzymes that hydrolyze esculin to esculetin and glucose.

Structure

Maltase-glucoamylase is a large protein composed of two similar domains, N- and C-terminal, each containing a catalytic site. The N-terminal domain preferentially hydrolyzes alpha-1,4-glucosidic bonds, such as those found in maltose, while the C-terminal domain is more effective at hydrolyzing alpha-1,6-glucosidic bonds, such as those found in isomaltose.

Function

The primary function of maltase-glucoamylase is to break down dietary starch and glycogen into glucose, which can then be used by the body for energy. This process occurs in the small intestine, where the enzyme is located on the surface of the intestinal brush border.

Clinical significance

Mutations in the MGAM gene can lead to congenital maltase-glucoamylase deficiency, a rare condition characterized by diarrhea and malabsorption of carbohydrates. This condition can be diagnosed through a biopsy of the small intestine or through genetic testing.

See also

• Sucrase-isomaltase
• Trehalase
• Lactase