Obtención y caracterización de inhibidores de pepsina provenientes de semillas de amaranto, arveja, chocho, fréjol, quinua o sangorache, mediante un sistema de purificación que emplee cromatografía de afinidad

Abstract

Pepsin inhibitors were obtained and characterized from certified seeds. As a first phase, the quinoa was determined as the aqueous extract with the greater specific inhibitory activity against pepsin (9,67 U/mg). Additionally, pepsin was immobilized by ion exchange in 6 mL of the DEAE-Sepharose CL-6B matrix at a selected pH of 2,0, due to the high amount of immobilized pepsin (24,72 mg) with the highest amount of functional activity retention (728 U). The partial purification of the quinoa extract was developed by centrifugal ultrafiltration which produced an AIE of 10.01 U / mg for the permeate and 9.85 U / mg for the retentate; followed by caloric treatment that achieved an AIE of 13.81 U / mg for the permeate and 18.15 U / mg for the retentate; and, saline precipitation reached an AIE of 22.25 and 22.77 U / mg for the permeate and retentate, respectively. The corresponding active fractions obtained by affinity chromatography of the semipurified permeate and retentate showed an AIE of 127.16 and 127.84 U / mg, correspondingly. The kinetic and molecular characterization determined the possible presence of a single inhibitor in the quinoa extract fractions of type non-competitive, with a molecular weight of 9.5 kDa. and an inhibition constant of 0.091 μM.