title: Primary sequence determination of a Kunitz inhibitor isolated from Delonix regia seeds.
abstract: A serine proteinase inhibitor was purified from Delonix regia seeds a Leguminosae tree of the Caesalpinioideae subfamily. The inhibitor named DrTI, inactivated trypsin and human plasma kallikrein with K(i )values 2.19x10(-8) M and 5.25 nM, respectively. Its analysis by SDS-PAGE 10-20% showed that the inhibitor is a protein with a single polypeptide chain of M(r) 22 h Da. The primary sequence of the inhibitor was determined by Edman degradation, thus indicating that it contained 185 amino acids and showed that it belongs to the Kunitz type family; however, its reactive site did not contain Arg or Lys at the putative reactive site (position 63, SbTI numbering) or it was displaced when compared to other Kunitz-type inhibitors.
authors.affiliation: Department of Biochemistry, Institute of Biology, UNICAMP, 13083-970, Campinas-SP, Brazil
authors.forename: S C
authors.initials: SC
authors.lastname: Pando
authors.forename: M L
authors.initials: ML
authors.lastname: Oliva
authors.forename: C A
authors.initials: CA
authors.lastname: Sampaio
authors.forename: L
authors.initials: L
authors.lastname: Di Ciero
authors.forename: J C
authors.initials: JC
authors.lastname: Novello
authors.forename: S
authors.initials: S
authors.lastname: Marangoni
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000196:embryology*; D008969:Molecular Sequence Data; D010455:Peptides; D010940:Plant Proteins; D010946:Plants, Medicinal; D012639:Seeds / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: C053865:Kunitz-type protease inhibitor, plant; D010455:Peptides; D010940:Plant Proteins; D014361:Trypsin Inhibitors