Heme oxygenase exerts a protective role against oxidative stress in soybean leaves.

NORIEGA GO; BALESTRASSE KB; BATLLE A; TOMARO ML

Argentina

Congreso; XL Reunión Nacional de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2004

We have previously demonstrated that the induction of heme oxygenase-1 (EC 1.14.99.3) plays a protective role for mammalian cells against oxidative stress. Here, we investigated for the first time the possible role of heme oxygenase-1 as an antioxidant defense in leaves of soybean plants. Treatment with 200 µM Cd during 48 h caused a 70% increase in thiobarbituric acid reactive substances, whereas GSH decreased 67%, guaiacol peroxidase and total superoxide dismutase were also inhibited 49% and 46%, respectively. 200 mM Cd produced the overexpression of heme oxygenase-1, as well as a 4.5 fold enhancement of its activity. Administration of biliverdin partially prevented the effects caused by Cd. Pretreatment with Zn protoporphyrin IX, a potent inhibitor of heme oxygenase, expectedly decreased heme oxygenase-1 activity to half. When the inhibitor was given before Cd, completely prevented the enzyme induction increasing the levels of oxidative stress parameters. Collectively these results indicated that although plant heme oxygenases share little homology to heme oxygenases from non-plant species, they also play an important protective role against oxidative cell damage.