ABSTRACT
Cytochrome c (Cc) is an evolutionarily conserved mitochondrial protein involved in cell life and death decisions. Similar to the photosynthetic soluble metalloproteins (Medina et al., 1992; Díaz et al., 1994a,b; Navarro et al., 1995; Molina-Heredia et al., 1999; Sun et al., 1999; Casaus et al., 2002; Crowley et al., 2002; Díaz-Moreno et al., 2005a,b,c), Cc participates in electron transfer (ET) as part of the mitochondrial respiratory chain, which is indispensable for energy production. Under apoptotic conditions, Cc is essential for the formation of the apoptosome (see Section 12.4.1) and triggering of cell death. is dual role of Cc is regulated by post-translational modications-namely, phosphorylation and nitration of tyrosine residues-that aect the binding of Cc to its physiological counterparts, either in the mitochondria or in the nucleus and/or cytoplasm.
