title: Primary structure of trypsin inhibitors from Sicyos australis.
abstract: Three trypsin inhibitors from Sicyos australis, have been isolated, purified and sequenced. Following protein extraction with ammonium sulphate, the mixture of inhibitors was separated from other proteins by trypsin-affinity chromatography. Subsequent purification of the individual inhibitors was accomplished by reversed-phase HPLC. The primary structures of each inhibitor were elucidated by a combination of protein sequencing and electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS-MS) on both the untreated and the reduced and S-carboxymethylated inhibitors. All three inhibitors show extensive sequence similarity with inhibitors from cultivated Cucurbitaceae species, although there are a number of novel residues present. One of the inhibitors has a blocked N-terminus (pyroglutamic acid) and the use of MS-MS was crucial to the elucidation of its primary structure. ESI-MS was further used to characterize the non-covalent complex between one of the inhibitors and trypsin.
authors.affiliation: Department of Chemistry, University of Wollongong, N.S.W., Australia.
authors.forename: R I
authors.initials: RI
authors.lastname: Mar
authors.forename: J A
authors.initials: JA
authors.lastname: Carver
authors.forename: M M
authors.initials: MM
authors.lastname: Sheil
authors.forename: J
authors.initials: J
authors.lastname: Boschenok
authors.forename: S
authors.initials: S
authors.lastname: Fu
authors.forename: D C
authors.initials: DC
authors.lastname: Shaw
mesh_terms: D000595:Amino Acid Sequence; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010944:Plants; D017386:Sequence Homology, Amino Acid; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D014675:Vegetables / Q000737:chemistry
chemical_list: D010446:Peptide Fragments; D014361:Trypsin Inhibitors