Compartmentalized nitrosation and nitration in mitochondria

A wide spectrum of the biological actions of nitric oxide and its oxidizing metabolites are mediated via mitochondria. Mitochondria are highly compartmentalized organelles consisting of three distinct compartments: the matrix, the intermembrane space, and the membranes. These compartments are different in their electrochemical properties, redox state, pH, enzymes, and ion content. Nitric oxide and its reactive species react within these compartments in distinct manners. The mitochondrial intermembrane space provides an environment that favors S-nitrosation, whereas nitration occurs largely within the matrix. This article will review some of the interactions of these species with certain mitochondrial respiratory chain complexes, apoptotic proteins, and enzymes. The reversibility and the suborganelle preference of these reactions will be discussed.