Iron and nitrosative metabolism in the Antarctic mollusc Laternula elliptica

. GONZALEZ P.M. Y PUNTARULO S.

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. TOXICOLOGY & PHARMACOLOGY

ELSEVIER SCIENCE INC

Año: 2011 vol. 153 p. 243 - 250

1532-0456

The objective of this work was to study, Fe distribution, oxidative and nitrosative metabolism in L. elliptica for physiological analysis and interspecific comparisons. Lipid peroxidation, superoxide dismutase and catalase activity and total Fe content were estimated in the digestive glands (DG) of L.elliptica. The labile Fe pool (LIP) represents the amount of cellular Fe responsible for catalyzing radical-dependent reactions. LIP assessed by the CA assay, represents 3.5% of the total Fe in L. elliptica. Experimental isolation of ferritin (Ft) was performed. Subunits analyses of the protein by SDS-polyacrilamide gel electrophoresis indicated that the protein was composed by 20.6 kDa protein subunits, consistent with the horse spleen Ft and the molecular weight markers, however, a higher molecular mass subunit could appear. The NO3-+NO2- content was 73±7 pmol/mg FW. The NO content in DG homogenates, assessed by EPR spin trapping measurements using the NO trap MGD-Fe at room temperature, was 30±2 pmol/mg FW. NOS-like activity (1.50 ± 0.09 pmol/mg FW min) was assessed by measuring NO production by EPR in the presence of L-Arginine (L-A) and NADPH. This activity was significantly inhibited by L-A analogs such as L-NAME (-77%) and L-NA (-62%), or by the lack of added L-A (-55%) The data presented here documented the presence of labile Fe, Ft and highly reactive nitrogen species, and are the first evidence that support the hypothesis that NO being generated in L. elliptica might contribute to restrict oxidative damage by a close link with Fe metabolism.