Mecanismos de regulación de la gliceraldehido-3-fosfato no fosforilante: Estudios sobre la fosforilación y la oxidoreducción de la enzima de trigo

PIATTONI, CV; GUERRERO, SA; BUSTOS, DM; IGLESIAS, AA

Chascomus, Buenos Aires

Congreso; Sociedad Argentina de Fisiologia Vegetal; 2006

Non-phosphorylating, NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase (EC: 1.2.1.9; NP-GaPDHase) is a cytosolic enzyme found photosynthetic eukaryotes. The enzyme is involved in a shuttle system exporting NADPH from chloroplasts to cytosol. In heterotrophic plant cells its function is less clear and it could couple NADPH production to glycolysis. In wheat endosperm (but not in leaves) NP-GaPDHase is post-translationally modified by phosphorylation, after which it interacts with 14 3-3 proteins. We heterologously expressed the gene encoding a NP-GaPDHase from wheat (NCBI; NºAcc:AF521191) and purified the enzymes to a high degree. NP-GaPDHase was inactivated by the thiol oxidative chemicals DTNB and Diamide. This inactivation was reverted by DTT and reduced thioredoxin, suggesting that NP-GaPDHase could be regulated by redox systems operating in the cytoplasm of plant cells.