Dipeptide

Glycylglycine

Dipeptide

A dipeptide is an organic compound derived from two amino acids joined by a single peptide bond. Dipeptides are among the simplest forms of peptides, which are short chains of amino acids. The formation of a dipeptide involves a condensation reaction where a molecule of water is released.

Structure

The general structure of a dipeptide consists of two amino acids linked by a peptide bond. The peptide bond is formed between the carboxyl group of one amino acid and the amino group of the other. The resulting molecule has a free amino group at one end (the N-terminus) and a free carboxyl group at the other end (the C-terminus).

Formation

Dipeptides are formed through a condensation reaction, also known as a dehydration synthesis. During this reaction, the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water and forming a peptide bond.

Examples

Some common examples of dipeptides include:

• Carnosine (β-alanyl-L-histidine)
• Anserine (β-alanyl-Nπ-methyl-L-histidine)
• Kyotorphin (L-tyrosyl-L-arginine)

Functions

Dipeptides play various roles in biological systems. They can act as neurotransmitters, antioxidants, and hormones. For example, carnosine is known for its antioxidant properties and is found in muscle tissues and the brain.

Hydrolysis

Dipeptides can be broken down into their constituent amino acids through a process called hydrolysis. This reaction involves the addition of a water molecule, which breaks the peptide bond, releasing the individual amino acids.

Related Pages

• Peptide
• Amino acid
• Protein
• Condensation reaction
• Hydrolysis

See Also

• Tripeptide
• Polypeptide
• Protein structure