Fig. 5.

Oxidative damage in mitochondrial subpopulations from WT and db/db hearts. Oxidative damage to lipids was assessed in mitochondrial subpopulations by measuring lipid peroxidation byproducts [malondialdehyde (MDA) and 4-hydroxyalkenal (4-HAE)] using a colorimetric assay and compared against a standard curve of known 4-HAE and MDA concentrations. Data are expressed in μmol MDA + 4-HAE/mg mitochondrial protein (A). Oxidative damage to proteins was assessed by quantifying 3-nitrotyrosine (NT) residues through a sandwich ELISA, and concentrations were determined by comparing results against a known protein NT standard curve. Results are expressed in nmol NT/mg protein (B). Values for both lipid peroxidation and protein nitrosylation are means ± SE; n = 5 for each group. *P < 0.05 for WT vs. db/db.