[Temperature transitions of spectrin in solution and in erythrocyte membranes]

Temperature transitions of spectrin in solution and in human erythrocyte membranes are recorded in the region t greater than 40 degrees C by irreversible changes in protein fluorescence spectra. Structural changes are completed 20 min after the sample incubation at an increased temperature. Both for isolated spectrin and for erythrocyte ghosts the temperature of half-transition is 46 +/- 1 degree C. There is no transition in the membranes after the removal of spectrin. Transitions in erythrocyte ghosts and in spectrin solution disappear at pH 5 when spectrin is in an aggregated state. Spectrin is suggested to be responsible for the transitions at 50 degrees C; its state in the cells areas more thermostable than in isolated membranes.