Isolation and Properties of a Kunitz-Type Protein Inhibitor Obtained from Pithecellobium dulce Seeds

We report for the first time the isolation and characterization of a protease inhibitor from the seeds of Pithecellobium dulce, which is a Leguminosae tree native to Mexico. The purification of the P. dulce trypsin inhibitor (PDTI) was a direct process. After its extraction (pH 8.0) and precipitatio...

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Bibliographic Details
Published in:Journal of agricultural and food chemistry 2004-10, Vol.52 (20), p.6115-6121
Main Authors: Delgado-Vargas, Francisco, López-Valdés, Héctor E, Valdés-Rodríguez, Silvia, Blanco-Labra, Alejandro, Chagolla-López, Alicia, López-Valenzuela, Erwin de J
Format: Article
Language:English
Subjects:
Amino Acid Sequence
amino acid sequences
Analytical, structural and metabolic biochemistry
anticarcinogenic activity
antinutritional factors
Biological and medical sciences
cytotoxicity
enzyme inhibition
Enzymes and enzyme inhibitors
Fabaceae - chemistry
food crops
Fundamental and applied biological sciences. Psychology
Hydrolases
medicinal plants
Molecular Sequence Data
Peptides - chemistry
Peptides - isolation & purification
Peptides - pharmacology
Pithecellobium dulce
Plant Proteins - chemistry
Plant Proteins - isolation & purification
Plant Proteins - pharmacology
purification
seeds
Seeds - chemistry
Sequence Analysis, Protein
Sequence Homology
trypsin
Trypsin - metabolism
trypsin inhibitors
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Summary:We report for the first time the isolation and characterization of a protease inhibitor from the seeds of Pithecellobium dulce, which is a Leguminosae tree native to Mexico. The purification of the P. dulce trypsin inhibitor (PDTI) was a direct process. After its extraction (pH 8.0) and precipitation (80% (NH4)2SO4), the pH was adjusted to 4.0, the supernatant was loaded onto a CM-Sepharose column, and a single peak of trypsin inhibitory activity was eluted (CM-TIA). The main component of CM-TIA was PDTI, a protein composed of two polypeptide chains joined by disulfide bridge(s), with a pI of 4.95 and a molecular weight determined by electrospray mass spectrometry of 19 614 Da. The N-terminal sequence of PDTI has the highest similarity with the seed inhibitor of Acacia confusa. PDTI lacks chymotrypsin inhibitory activity. A low rate of cytotoxicity of CM-TIA toward RINm5F cells contrasted with a high rate of the active fraction G75-TIA (gel filtration chromatography; LC50 of 0.04 mg/mL). Keywords: Pithecellobium dulce; seed protein; cytotoxicity; Kunitz inhibitor; trypsin inhibitor
ISSN:0021-8561
1520-5118
DOI:10.1021/jf049694b