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Isolation and Characterization of a New Trypsin Inhibitor from Crotalaria paulina Seeds
Author(s) -
Pando Luiza A.,
Ciero Luciana Di,
Novello Jose C.,
Oliveira Benedito,
Weder Jurgen K. P.,
Marangoni Sergio
Publication year - 1999
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/713803553
Subject(s) - trypsin , isoelectric point , trypsin inhibitor , kunitz sti protease inhibitor , chemistry , biochemistry , chromatography , serine , glycine , amino acid , size exclusion chromatography , isoelectric focusing , enzyme
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 K i 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.