Detection and characterization of a new metallocarboxypeptidase inhibitor from Solanum tuberosum cv. Desirèe using proteomic techniques

OBREGÓN, WALTER D.; GHIANO, NATALIA; TELLECHEA MARIANA; CISNEROS J.S.; LAZZA, CRISTIAN M.; LÓPEZ, LAURA; AVILÉS, X.F.

FOOD CHEMISTRY

ELSEVIER SCI LTD

Lugar: cambridge; Año: 2011

0308-8146

Protease inhibitors have been considered only as long as anti-nutritional factors, but have regained much interest in recent years because of their potential anti-cancer action and also because of its positive dietary effects. A new potato carboxypeptidase inhibitor (PCI) was isolated using proteomics techniques; the inhibitor was detected in an extract of Solanum tuberosum cv. Desirée by intensity fading MALDI-TOF mass spectrometry, and then was purified and characterised. The mass spectral from tryptic digestion (peptide mass  fingerprint) was analysed with the ‘‘MASCOT search tool’’ and did not match any of the inhibitors of other plants. Protein identification and differentiation by peptide mass  fingerprinting (PMF) has been adopted in our group as an excellent tool to differentiate, in fast an unequivocal way, proteins with very similar physicochemical and functional properties. The new PCI exhibited a molecular mass of 4218 Da and consists of a single polypeptide chain with an isoelectric point of 6.5. MALDI- TOF/TOF sequence analysis allowed determines a sequence belonging to the inhibitor.