title: Amino acid sequence and disulfide bridges of affinity purified Kunitz-type chymotrypsin inhibitor from winged bean seed (Psophocarpus tetragonolobus (L.) DC).
abstract: The primary sequence of the affinity purified chymotrypsin inhibitor, WBCI, isolated from the albumin fraction of Psophocarpus tetragonolobus (L.) DC cv. UPS-122 seed was determined. The inhibitor consisted of a single polypeptide chain of 183 amino acids (Mr 20285) and the four half-cystine residues in the molecule formed two intramolecular disulfide bridges equivalent to those in other Kunitz-type seed inhibitors. The sequence of this chymotrypsin inhibitor was identical to that of chymotrypsin inhibitor-3 from cultivar UPS-31 and it showed about 50% sequence similarity to the winged bean acidic (WBTI-2, pI 5.1) and basic (WBTI-1, pI 8.9) trypsin inhibitors. Sequence similarities to other Kunitz-type seed inhibitors are discussed.
authors.affiliation: CSIRO, Division of Biomolecular Engineering, Parkville Laboratory, Victoria, Australia.
authors.forename: A A
authors.initials: AA
authors.lastname: Kortt
authors.forename: J E
authors.initials: JE
authors.lastname: Burns
authors.forename: P M
authors.initials: PM
authors.lastname: Strike
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002846:Chromatography, Affinity; D004220:Disulfides / Q000032:analysis; D007887:Fabaceae / Q000032:analysis*; D008969:Molecular Sequence Data; D010940:Plant Proteins; D010946:Plants, Medicinal; D012689:Sequence Homology, Nucleic Acid; D014361:Trypsin Inhibitors / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D004220:Disulfides; D010940:Plant Proteins; D014361:Trypsin Inhibitors; C440588:WCI protein, Psophocarpus tetragonolobus