title: Primary structure of Dioclea glabra trypsin inhibitor, DgTI, a Bowman-Birk inhibitor.
abstract: A novel serine proteinase inhibitor, DgTI, was purified from Dioclea glabra seeds by acetone precipitation, and ion-exchange and reverse phase chromatography. The inhibitor belongs to the Bowman-Birk family, and its primary sequence, determined by Edman degradation and mass spectrometry, of 67 amino acids is: SSGPCCDRCRCTKSEPPQCQCQDVRLNSCHSACEACVCSHSMPGLCSCLDITHFCHEPCKSSGDDED++ +. Although two reactive sites were determined by susceptibility to trypsin (Lys(13) and His(40)), the inhibitory function was assigned only to the first site. The inhibitor forms a 1:1 complex with trypsin, and Ki is 0.5 x 10(-9) M. Elastase, chymotrypsin, kallikreins, factor Xa, thrombin, and plasmin were not inhibited. By its properties, DgTI is a Bowman-Birk inhibitor with structural and inhibitory properties between the class of Bowman-Birk type I (with a fully active second reactive site), and Bowman-Birk type II (devoid of second reactive site).
authors.affiliation: Departamento de Bioquímica, Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Três de Maio, 100, São Paulo, SP, 04044-020, Brazil.
authors.forename: N R
authors.initials: NR
authors.lastname: Bueno
authors.forename: H
authors.initials: H
authors.lastname: Fritz
authors.forename: E A
authors.initials: EA
authors.lastname: Auerswald
authors.forename: R
authors.initials: R
authors.lastname: Mentele
authors.forename: M
authors.initials: M
authors.lastname: Sampaio
authors.forename: C A
authors.initials: CA
authors.lastname: Sampaio
authors.forename: M L
authors.initials: ML
authors.lastname: Oliva
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002845:Chromatography; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D012639:Seeds / Q000737:chemistry; D017385:Sequence Homology; D013696:Temperature; D014357:Trypsin / Q000378:metabolism; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000737:chemistry; D014361:Trypsin Inhibitors / Q000737:chemistry*
chemical_list: C120964:DgTI protein, Dioclea glabra; D010940:Plant Proteins; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D014361:Trypsin Inhibitors; D014357:Trypsin