Fusion of Sulfatide‐Containing Vesicles of Phosphatidylcholine

Abstract

Positively charged albumin is described as a ‘useful tool’ to induce both aggregation and fusion of phosphatidylcholine vesicles containing sulfatide. Techniques that include light‐scattering, Sepharose chromatography, centrifugation, electron microscopy, trapped volume determination and scanning calorimetry demonstrate that extensive fusion occurs during aggregation when sulfatide concentrations are above 4–5 mol%. The rate of fusion increases with time for 1–2 h, then reaches a plateau. Fusion occurs extensively above the transition temperature of the phospholipid and is strongly inhibited by increasing concentration of vesicle cholesterol. The significance of both membrane fluidity and sulfatide‐phospholipid organization in the fusion mechanism are discussed.