EFFECT OF CARDIOLIPIN ON FUNCTIONAL-PROPERTIES OF ISOLATED RAT-LIVER MITOCHONDRIA

The specific involvement of cardiolipin in modulating and/or controlli ng the activity of a number of mitochondrial carriers, enzymes and rec eptors is well documented; however, comparatively less understood is i ts role for the integrated functions of intact mitochondria. The aim o f the present research was to get a better insight into this problem b y investigating the effect of in vitro addition of cardiolipin on the properties of isolated liver mitochondria. The results obtained show t hat cardiolipin induces extensive structural and functional perturbati ons at the level of the inner mitochondrial membrane. In fact, additio n of cardiolipin to intact mitochondria causes a significant increase of proton leak associated with a parallel increase of respiratory rate in State 4. Concomitantly, a slight uncoupling of phosphorylation ass ociated with a moderate increase in ATPase activity is observed. Furth ermore, the pore-mediated membrane permeability to calcium is drastica lly modified, an effect that can be reversed by addition of cyclospori n.