title: Isolation and characterization of a new trypsin inhibitor from Crotalaria paulina seeds.
abstract: A new trypsin inhibitor (CPTI) has been isolated from Crotalaria paulina seeds. Purification of the inhibitor was carried out by gel filtration, ion-exchange chromatography, and subsequent reversed-phase HPLC. The presence of a single polypeptide chain, with a molecular mass of 20 kDa and isoelectric point 4.0, was detected. The trypsin inhibitor had a Ki value of 4.5 x 10(-8) M and was capable of acting on human, bovine, and porcine trypsin and weakly on bovine chymotrypsin. Amino acid analysis showed that CPTI has a high content of aspartate, glutamate, leucine, serine, and glycine, having 177 amino acid residues in its composition. These data suggest that the protein belongs to the Kunitz-type trypsin inhibitors.
authors.affiliation: Departamento de Bioquímica, Instituto de Biologia, Campinas, SP, Brasil.
authors.forename: L A
authors.initials: LA
authors.lastname: Pando
authors.forename: L
authors.initials: L
authors.lastname: Di Ciero
authors.forename: J C
authors.initials: JC
authors.lastname: Novello
authors.forename: B
authors.initials: B
authors.lastname: Oliveira
authors.forename: J K
authors.initials: JK
authors.lastname: Weder
authors.forename: S
authors.initials: S
authors.lastname: Marangoni
mesh_terms: D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000037:antagonists & inhibitors / Q000378:metabolism; D007887:Fabaceae / Q000201:enzymology*; D006736:Horses; D006801:Humans; D007525:Isoelectric Focusing; D007700:Kinetics; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010946:Plants, Medicinal; D012639:Seeds / Q000201:enzymology; D013552:Swine; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D010936:Plant Extracts; D014361:Trypsin Inhibitors; D002918:Chymotrypsin; D014357:Trypsin