A new family of growth factor-like peptides. 'Trefoil' disulphide loop structures as a common feature in breast cancer associated peptide (pS2), pancreatic spasmolytic polypeptide (PSP), and frog skin peptides (spasmolysins)

FEBS Lett. 1989 Jun 19;250(1):85-90. doi: 10.1016/0014-5793(89)80690-8.


Four peptides present in completely different biological sources have been shown to exhibit a large degree of structural similarity. The peptides include: (i) a 60 amino acid residue breast cancer associated pS2 peptide isolated from human gastric juice and the culture media of the human breast cancer cell line MCF-7; (ii) a 106 amino acid residue pancreatic spasmolytic polypeptide (PSP) isolated from porcine pancreas and pancreatic juice; and (iii) a 49 and 50 amino acid residue peptide predicted from a cDNA isolated from the skin of the frog, Xenopus laevis. These peptides are characterized by having one (pS2 and the frog peptides) or two (PSP) domains of a highly conserved 38-39 amino acid residue consensus sequence not found in any other known peptides or proteins. The domain sequences contain 6 cysteine residues in nearly the same positions and it is suggested that these 6 residues are linked by 3 disulphide bonds to form a characteristic 'trefoil' disulphide loop structure common in all four peptides. From the sources of which the peptides have been isolated and from experiments showing that PSP has a growth factor stimulatory effect on MCF-7 cells, it is further suggested that these peptides may represent members of a new family of growth factors.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Breast Neoplasms
  • Cell Line
  • Female
  • Gastric Juice / analysis
  • Growth Substances / genetics*
  • Humans
  • Intercellular Signaling Peptides and Proteins
  • Models, Molecular
  • Molecular Sequence Data
  • Mucins*
  • Muscle Proteins*
  • Neuropeptides*
  • Parasympatholytics
  • Peptides / genetics*
  • Protein Conformation
  • Sequence Homology, Nucleic Acid
  • Trefoil Factor-2
  • Trefoil Factor-3
  • Xenopus laevis


  • Growth Substances
  • Intercellular Signaling Peptides and Proteins
  • Mucins
  • Muscle Proteins
  • Neuropeptides
  • Parasympatholytics
  • Peptides
  • TFF3 protein, rat
  • Tff2 protein, rat
  • Trefoil Factor-2
  • Trefoil Factor-3
  • pancreatic spasmolytic polypeptide