IAL   21557
INSTITUTO DE AGROBIOTECNOLOGIA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Characterization of Entamoeba histolytica UDPglucose Pyrophosphorylase. Studies on Redox Regulation
Autor/es:
L.I. MARTÍNEZ, S.A. GUERRERO, A.A. IGLESIAS
Lugar:
Villa Carlos Paz, Córdoba, Argentina
Reunión:
Congreso; XLIII Reunión Anual de SAIB; 2008
Institución organizadora:
SAIB
Resumen:
EN-P09.CHARACTERIZATION OF Entamoeba histolytica UDPGLCPYROPHOSPHORYLASE.STUDIES ON REDOXREGULATIONMartínez LI, Guerrero SA, Iglesias AA.CONICET-UNL, Lab. Enzimología Molecular y Bioq. Microbiana,FBCB. Santa Fe. E-mail: lucilama@fbcb.unl.edu.arAmoebiasis is an intestinal infection caused by the human pathogenEntamoeba histolytica. The parasitic disease is the third leadingcause of death in the world (100,000 deaths annually). E. histolyticadisplays anchored-cell surface glycoconjugates involved in hostparasiteinteractions. The pathways for biosynthesis ofglycoconjugates have not yet been fully elucidated. In parasiticorganisms the production of structural oligo- and polysaccharidesoccurs via UDPGlc; with UDPGlc pyrophosphorylase (EC 2.7.7.9;UDPGlcPPase) catalyzing its synthesis. We report the molecularcloning of the gene coding for UDPGlcPPase from genomic DNA ofE. histolytica. We used BL21(DE3)/pRSETB for expression andconvenient purification of the recombinant His-tag protein product.The purified enzyme exhibited typical hyperbolic saturation kineticsfor substrates. The enzyme activity was affected by redoxmodification of thiol groups. Different oxidants, including diamide,hydrogen peroxide and sodium nitroprusside inactivated theenzyme. The process was conveniently reversed by reducing agents,mainly DTT and thioredoxins from E. histolitica and Trypanosomabrucei. Results suggest the occurrence of a physiological redoxmechanism for modulation of UDPGlcPPase activity, which wouldbe critical to regulate carbohydrates metabolism in protozoa.Granted by CAI+D 2006, PAV 137 and PICTO’06 15-36129.