[Phase transitions of model and biological membranes. II. Temperature-dependent structural reorganization of sarcoplasmic reticulum membranes].

Temperature-dependent structural transitions of sarcoplasmic reticulum membranes, Ca2+-activated ATPase from membranes and liposomes formed from total membrane lipids were studied by fluorescent probes such as 3-metoxybenzantron and dimetylaminochalkon. It was found that sarcoplasmic reticulum membranes undergo the structural transitions at 10, 17--18, 30, 41--43 and 49 degrees C; lipids at 14--15, 30 degrees C and ATPase at 47--49 degrees C. The data obtained here indicate that transitions at 10, 17--18 and 30 degrees C in sarcoplasmic reticulum membranes are associated with a melt of lipids, while the transitions at 41--43 and 49 degrees C apparently reflect changes in conformation of membrane proteins.