Abstract
Rabbit sarcoplasmic reticulum does contain trace amounts of gangliosides, and the main species is GM3. Incorporation of GM3 into the SR vesicles or addition of it to the soybean phospholipid used for reconstitution of proteoliposomes obviously increased ATP hydrolysis, as well as, Ca2+ uptake activity of sarcoplasmic reticulum Ca2+-ATPase. Conformation changes of Ca2+-ATPase induced by GM3 were also observed by circular dichroism, intrinsic fluorescence and fluorescence quenching measurements.