1. A trypsin inhibitor from Sapindus saponaria L. seeds: purification, characterization, and activity towards pest insect digestive enzyme.
- Author
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Macedo ML, Diz Filho EB, Freire MG, Oliva ML, Sumikawa JT, Toyama MH, and Marangoni S
- Subjects
- Amino Acid Sequence, Animals, Arginine chemistry, Brazil, Dithiothreitol chemistry, Dithiothreitol pharmacology, Drug Stability, Hydrogen-Ion Concentration, Insecticides chemistry, Insecticides pharmacology, Intestine, Small enzymology, Kinetics, Larva enzymology, Molecular Sequence Data, Molecular Weight, Plant Proteins chemistry, Plant Proteins pharmacology, Protein Stability, Trypsin Inhibitors chemistry, Trypsin Inhibitors pharmacology, Insecticides isolation & purification, Lepidoptera, Plant Proteins isolation & purification, Sapindus chemistry, Seeds chemistry, Trypsin Inhibitors isolation & purification
- Abstract
The present paper describes the purification, characterization and determination of the partial primary structure of the first trypsin inhibitor isolated from the family Sapindaceae. A highly stable, potent trypsin inhibitor (SSTI) was purified to homogeneity. SDS-PAGE analysis revealed that the protein consists of a two-polypeptide chain with molecular masses of approximately 15 and 3 kDa. The purified inhibitor inhibited bovine trypsin at a 1:1 M ratio. Kinetic analysis revealed that the protein is a competitive inhibitor with an equilibrium dissociation constant of 10⁻⁹ M for trypsin. The partial NH₂- terminal sequence of 36 amino acids in SSTI indicates homology with other members of the trypsin-inhibitor family from different sources. This inhibitor is highly stable in the presence of denaturing agents. SSTI showed significant inhibitory activity against trypsin-like proteases present in the larval midgut on Anagasta kuehniella, Corcyra cephalonica, Diatreae saccharalis and Anticarsia gemmatalis.
- Published
- 2011
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