EFFECT OF ARSENIC ON NADPH GENERATING ENZYMES IN SOYBEAN (GLYCINE MAX. L)

ROSSI F,; MARSÁ S,; ZIRULNIK F.

Potrero de los Funes-San Luis

Congreso; CUYO BIOLOGY SOCIETY XXIV Annual Scientific Meeting; 2006

Sociedad de Biologia de Cuyo

Species of inorganic arsenic produce oxidative stress, generating free radicals and reactive oxygen species. These species react with lipids, proteins, pigments and nucleic acids, producing lipoperoxidation, enzymatic inactivation, so affecting the cellular viability. The role of NADPH generating enzymes as NADP-isocitrate dehydrogenase (ICD) in the antioxidative response of soybean leaves and roots to arsenic contamination was studied. Grown plants were exposed on the 10th day of adaptation to hydroponic conditions in Hoagland’s solution to intoxication with arsenic (6 and 16 uM) during 24 and 72 hours. The enzymatic activity of ICD was determined in soybean leaves and roots. The results showed a significant increase at short time (24h) with treatment I (6uM) and at long time (72h) with treatment II (16uM), in leaves (p < 0.001). Roots showed an increase of the specific activity at 24h with treatment I (p < 0.05).We can suggest that arsenic alters the NADPH production, demonstrating an essential role of this cofactor to maintain the reduction equivalents on the GSH-GSSG system, as part of the antioxidative defense responses, depending on the arsenic concentration and the time of treatment.