SPERMINE BINDING TO LIVER-MITOCHONDRIA

Non-equilibrium binding of spermine to mitochondrial membranes is stud ied in rat liver mitochondria by applying a new thermodynamic treatmen t of ligand-receptor interactions (Di Note, V., Dalla Via, L., Toninel lo, A. and Vidali, M. (1996) Macromol. Theory Simul. 5, 165-181). The presence on mitochondrial membranes of two spermine binding sites, bot h with monocoordination, is demonstrated. The calculated binding energ y is characteristic for weak interactions. The treatment allows also t o evaluate the variations of the molar fraction ratio of spermine boun d to sites 1 and 2 as function of total bound spermine. The possible r ole of the two sites is discussed.