Oligopeptide

An oligopeptide is a short chain of amino acids, typically consisting of 2 to 20 amino acids linked by peptide bonds.

  • The prefix “oligo–” means “few”.
  • Oligopeptides are shorter than polypeptides and much shorter than proteins.

They can occur naturally or be synthesized in labs and often serve specialized functions in signaling, regulation, or immune defense.

🧠 How Are Oligopeptides Classified?

Oligopeptides fall within the broader peptide category and are often grouped as:

TypeNumber of Amino Acids
Dipeptide2 amino acids
Tripeptide3 amino acids
Tetrapeptide4 amino acids
Pentapeptide5 amino acids
OligopeptideGenerally 2–20 amino acids

🔬 Functions of Oligopeptides

Though short, oligopeptides can perform powerful functions:

✅ Common Biological Roles:

  • Hormonal signals (e.g. TRH – a tripeptide)
  • Immune defense (e.g. defensins, which are antimicrobial oligopeptides)
  • Neurotransmission (e.g. enkephalins, small opioid peptides)
  • Antioxidant activity (e.g. glutathione – a tripeptide antioxidant)
  • Cell signaling (affecting inflammation, growth, or healing)

🧪 Examples of Natural Oligopeptides:

OligopeptideLengthFunction
Glutathione3 AAsAntioxidant, detoxification
TRH (Thyrotropin-RH)3 AAsStimulates TSH release from the pituitary
Enkephalins5 AAsNatural pain relief (opioid activity)
Angiotensin II8 AAsRegulates blood pressure
Defensins~18–20 AAsKill bacteria, part of innate immunity

💊 Oligopeptides in Medicine & Cosmetics

Many synthetic oligopeptides are used in:

  • Skin care: anti-aging and collagen-boosting peptides (e.g., Matrixyl)
  • Wound healing: tissue-repair peptides (e.g., copper peptides)
  • Therapeutics: insulin mimetics, anti-inflammatory peptides, immune boosters
  • Research: used to study protein structure and receptor interaction

🧠 Summary Table:

FeatureOligopeptide
Size2–20 amino acids
Bond typePeptide bonds
FunctionHormonal, signaling, immune, metabolic
Found inHormones, neurotransmitters, immune cells
UsesMedical therapy, cosmetics, lab research
Compared to proteinMuch smaller and more specialized