Definition
A peptide with exactly 9 amino acid residues.

Detailed Explanation

A peptide with exactly 9 amino acid residues. The most famous nonapeptides are the structurally related hormones oxytocin (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂) and vasopressin (Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH₂), which differ at only two positions (3 and 8) yet have dramatically different functions — oxytocin regulates bonding and reproduction while vasopressin controls water balance and blood pressure.

Both contain a disulfide bridge forming a 6-residue ring. Other notable nonapeptides include bradykinin (9 aa, vasodilation and pain) and desmopressin (synthetic vasopressin analog used to treat diabetes insipidus and bedwetting).

Key Facts

  • A peptide with exactly 9 amino acid residues.
  • The most famous nonapeptides are the structurally related hormones oxytocin (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂) and vasopressin (Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH₂), which differ at only two positions (3 and 8) yet have dramatically different functions — oxytocin regulates bonding and reproduction while vasopressin controls water balance and blood pressure.
  • Both contain a disulfide bridge forming a 6-residue ring.
  • Other notable nonapeptides include bradykinin (9 aa, vasodilation and pain) and desmopressin (synthetic vasopressin analog used to treat diabetes insipidus and bedwetting).
Related Terms Oxytocin Vasopressin Bradykinin Dipeptide Tripeptide Oligopeptide

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