IAL   21557
INSTITUTO DE AGROBIOTECNOLOGIA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Redox Regulation of Glycolytic Triose-P Branch Point in the Cytosol of Wheat Cells
Autor/es:
C.V. PIATTONI; S.A. GUERRERO; A.A. IGLESIAS
Lugar:
San Miguel de Tucumán, Argentina
Reunión:
Congreso; XLV Reunión Anual de SAIB; 2009
Institución organizadora:
SAIB
Resumen:
PL-C02.REDOX REGULATION OF GLYCOLYTIC TRIOSE-PBRANCH POINT IN THE CYTOSOL OF WHEAT CELLSPiattoni CV; Guerrero SA; Iglesias AAIAL (UNL-CONICET), Lab. de Enzimología Molecular y Lab. deBioquímica Microbiana, FBCB, Santa Fe. E-mail:piattoni@fbcb.unl.edu.arIn plant cells, one of the key points in cytosolic glycolysis involvesthe conversion of glyceraldehyde-3-phosphate (Ga3P) into 3-PGA.In order to understand the fate of triose-P, we studied posttranslationalmodifications of two different plant cytosolic Ga3Pdehydrogenases: the phosphorylating enzyme (p-Ga3PDHase, EC1.2.1.12) [that followed by the 3P-glycerate kinase derives triose-Pto the synthesis of ATP and NADH], and the non-phosphorylatingenzyme (np-Ga3PDHase; EC 1.2.1.9) [that leads triose-P to thesynthesis of NADPH]. We found that both enzymes can be regulatedvia redox modification (by ROS and RSN), being the p-Ga3PDHasemarkedly more sensitive to thiol oxidants than np-Ga3PDHase.Concurrently, p-Ga3PDHase is oxidized by H O with a k” of 119 M- 2 21s-1, which is 63-fold higher than that obtained for np-Ga3PDHaseoxidation. The loss of activity was effectively reversed afterincubation with physiological reductans as GSH, reduced TRX-hand reduced GRX. After results, it is tempting to speculate that underoxidative conditions the cytosolic fate of triose-P is routed toNADPH generation rather than to ATP and NADH. The redoxmodification mechanism, together with the regulation of bothGa3PDHases by reversible phosphorylation (and interaction with14-3-3 regulatory proteins) strongly suggests that the cytosolicGa3P oxidation step in plant cells is under strict control.