A dipeptide is a molecule made of two amino acids linked together by a single peptide bond.
- “Di–” means two
- “Peptide” refers to a short chain of amino acids connected via peptide bonds
Dipeptides are the simplest form of peptides beyond a single amino acid, and they often serve as intermediates in digestion, metabolism, and signaling.
🔗 How Is a Dipeptide Formed?
- A peptide bond is formed through a dehydration reaction:
- The carboxyl group (-COOH) of one amino acid reacts with the amino group (-NH₂) of another.
- This releases a molecule of water (H₂O) and links the two amino acids.
🧪 Examples of Dipeptides
| Dipeptide | Amino Acids | Function |
|---|---|---|
| Carnosine | β-alanine + histidine | Antioxidant, found in muscle and brain tissues |
| Aspartame | Aspartic acid + phenylalanine | Artificial sweetener |
| Anserine | β-alanine + 1-methylhistidine | Muscle buffer, antioxidant |
🍽️ Dipeptides in Digestion
- During protein digestion, enzymes like pepsin and trypsin break down proteins into smaller peptides, including dipeptides.
- These dipeptides are then absorbed in the small intestine using special peptide transporters.
- Inside intestinal cells, they are broken down into individual amino acids and absorbed into the bloodstream.
🧠 Functional Roles of Dipeptides:
- Fast absorption compared to whole proteins or longer peptides
- Can act as neurotransmitters, antioxidants, or enzyme inhibitors
- Used in sports nutrition (e.g., carnosine for performance and recovery)
- Studied for anti-aging, anti-inflammatory, and brain health benefits
🧠 Summary Table:
| Feature | Dipeptide |
|---|---|
| Composition | 2 amino acids |
| Bond type | 1 peptide bond |
| Role in digestion | Intermediate step in breaking down proteins |
| Common uses | Nutrition, sweeteners, antioxidant support |
| Examples | Carnosine, aspartame, anserine |