Primary structure of Dioclea glabra trypsin inhibitor, DgTI, a Bowman-Birk inhibitor.
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).
Bueno
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NR
Departamento de Bioquímica, Universidade Federal de São Paulo-Escola Paulista de Medicina, Rua Três de Maio, 100, São Paulo, SP, 04044-020, Brazil.
Fritz
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H
Auerswald
E A
EA
Mentele
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R
Sampaio
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M
Sampaio
C A
CA
Oliva
M L
ML
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*
C120964:DgTI protein, Dioclea glabra; D010940:Plant Proteins; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D014361:Trypsin Inhibitors; D014357:Trypsin