title: Purification and characterization of a trypsin inhibitor from Plathymenia foliolosa seeds.
abstract: A novel trypsin inhibitor (PFTI) was isolated from Plathymenia foliolosa (Benth.) seeds by gel filtration chromatography on a Sephadex G-100, DEAE-Sepharose, and trypsin-Sepharose columns. By SDSPAGE, PFTI yielded a single band with a M(r) of 19 kDa. PFTI inhibited bovine trypsin and bovine chymotrypsin with equilibrium dissociation constants (K(i)) of 4 x 10(-8) and 1.4 x 10(-6) M, respectively. PFTI retained more than 50% of activity at up to 50 degrees C for 30 min, but there were 80 and 100% losses of activity at 60 and 70 degrees C, respectively. DTT affected the activity or stability of PFTI. The N-terminal amino acid sequence of PFTI showed a high degree of homology with various members of the Kunitz family of inhibitors. Anagasta kuehniella is found worldwide; this insect attacks stored grains and products of rice, oat, rye, corn, and wheat. The velvet bean caterpillar (Anticarsia gemmatalis) is considered the main defoliator pest of soybean in Brazil. Diatraea saccharalis, the sugar cane borer, is the major pest of sugar cane crops, and its caterpillar-feeding behavior, inside the stems, hampers control. PFTI showed significant inhibitory activity against trypsin-like proteases present in the larval midguts on A. kuehniella and D. saccharalis and could suppress the growth of larvae.
authors.affiliation: Departamento de Bioquímica/Instituto de Biologia, Universidade Estadual de Campinas, SP, Brazil.
authors.forename: Vanessa da Silveira
authors.initials: Vda S
authors.lastname: Ramos
authors.forename: Gilvânia de Souza
authors.initials: Gde S
authors.lastname: Silva
authors.forename: Maria das Graças Machado
authors.initials: Md
authors.lastname: Freire
authors.forename: Olga Lima Tavares
authors.initials: OL
authors.lastname: Machado
authors.forename: José Roberto Postali
authors.initials: JR
authors.lastname: Parra
authors.forename: Maria Lígia Rodrigues
authors.initials: ML
authors.lastname: Macedo
mesh_terms: D000595:Amino Acid Sequence; D007887:Fabaceae / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012639:Seeds / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014361:Trypsin Inhibitors