SPERMINE BINDING TO LIVER-MITOCHONDRIA DEENERGIZED BY RUTHENIUM RED PLUS EITHER FCCP OR ANTIMYCIN-A

Thermodynamic analysis of spermine binding to mitochondria treated wit h ruthenium red and deenergized with either FCCP or antimycin A confir ms the presence of two polyamine binding sites, S-1 and S-2, both with monocoordination, as previously observed in energized mitochondria [D alla Via et al., Biochim, Biophys. Acta 1284 (1996) 247-252], Both sit es undergo a marked change in binding capacity and binding affinity up on mitochondrial deenergization. This change is most likely responsibl e for the incomplete or delayed spermine-mediated inhibition of the pe rmeability transition induced in deenergized mitochondria. (C) 1998 Fe deration of European Biochemical Societies.