title: 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).
abstract: 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.
authors.affiliation: Novo Research Institute, Bagsvaerd, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Thim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001943:Breast Neoplasms; D002460:Cell Line; D005260:Female; D005750:Gastric Juice / Q000032:analysis; D006133:Growth Substances / Q000235:genetics*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009077:Mucins; D009124:Muscle Proteins; D009479:Neuropeptides; D010276:Parasympatholytics; D010455:Peptides / Q000235:genetics*; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; D014982:Xenopus laevis
chemical_list: D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D009077:Mucins; D009124:Muscle Proteins; D009479:Neuropeptides; D010276:Parasympatholytics; D010455:Peptides; C099037:TFF3 protein, rat; C000604008:Tff2 protein, rat; D000071164:Trefoil Factor-2; D000071165:Trefoil Factor-3; C034407:pancreatic spasmolytic polypeptide