Temperature dependence of N-phenyl-1-naphthylamine binding in egg lecithin vesicles.
The temperature dependence of the binding of PhNapNH2 (N-phenyl-1-naphthylamine) to vesicles of egg phosphatidylcholine has been determined. The Arrhenius plot of the association constant exhibits a discontinuity at 20.9 degrees C, some 30 degrees C above the broad phase transition region of the phospholipid. In the temperature range above 20 degrees C, deltaH0 =--6100 cal-mol-1 and deltaS0 = 9.7 e.u.; in the temperature range below 20 degrees C, deltaH0 = 0 cal-mol-1 and deltaS0 = 30.4 e.u. These values are consistent with the view that there are well ordered lipid-lipid bonds below 20 degrees C which are significantly less important above this temperature. The order in the temperature range of 5 to 20 degrees C, though significantly greater than that above 20 degrees C, is still significiantly less than that in the crystalline state.
D015057:1-Naphthylamine; D001665:Binding Sites; D002151:Calorimetry; D004530:Egg Yolk; D005260:Female; D008567:Membranes, Artificial; D008954:Models, Biological; D009281:Naphthalenes; D010713:Phosphatidylcholines; D013696:Temperature; D013816:Thermodynamics
D008567:Membranes, Artificial; D009281:Naphthalenes; D010713:Phosphatidylcholines; D015057:1-Naphthylamine