Dipeptidase

Dipeptidase

Structure of a dipeptidase enzyme.

Dipeptidase is an enzyme that plays a crucial role in the digestion and absorption of proteins in the human body. It is responsible for breaking down dipeptides, which are molecules composed of two amino acids linked together by a peptide bond. Dipeptidases are found in various tissues and organs, including the small intestine, kidney, and liver.

Structure

Dipeptidases belong to the class of enzymes known as hydrolases, specifically peptidases. They are typically membrane-bound proteins, with their active sites located on the extracellular side of the cell membrane. The structure of dipeptidases varies among different organisms, but they generally consist of a single polypeptide chain with multiple domains.

Function

The primary function of dipeptidases is to hydrolyze dipeptides into individual amino acids. This process occurs in the small intestine, where dipeptides are generated during the breakdown of dietary proteins by proteases. Dipeptidases play a crucial role in the final stages of protein digestion, as they convert dipeptides into amino acids that can be readily absorbed by the intestinal cells.

Mechanism of Action

Dipeptidases catalyze the hydrolysis of the peptide bond between the two amino acids in a dipeptide molecule. This process involves the addition of a water molecule, which breaks the bond and forms two separate amino acids. The active site of the dipeptidase enzyme facilitates this reaction by providing the necessary environment for the substrate binding and catalysis to occur.

Importance in Health and Disease

Dipeptidases are essential for the proper digestion and absorption of dietary proteins. Without these enzymes, the body would not be able to efficiently break down dipeptides into individual amino acids, leading to impaired nutrient absorption. Deficiencies or abnormalities in dipeptidase activity can result in various digestive disorders, such as malabsorption syndromes.

Furthermore, dipeptidases have been implicated in the regulation of blood pressure. Some dipeptidases, such as angiotensin-converting enzyme (ACE), are involved in the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. Inhibitors of ACE, commonly known as ACE inhibitors, are widely used as antihypertensive drugs.

See Also

• Protease
• Amino acids
• Digestive system
• Malabsorption syndrome
• Angiotensin-converting enzyme