Isolation of a plasma membrane fraction highly enriched in ouabain-sensitive Na ++-ATPase from rat brain white matter

Abstract

1. 1. A plasma membrane fraction was isolated from the rat brain white matter. 2. 2. Briefly, a washed paniculate fraction (10,000 g pellet) was exposed to hypo-osmotic buffer followed by a brief sonication and was then fractionated by two successive sucrose density gradient centrifugations. The particle bands obtained at 25–32% (w/v) sucrose interface and in 32% sucrose suspension were highly enriched in the ouabain-sensitive Na +K +-ATPase (200–250 μmo P i,/mg of protein/hr), and were considered to represent highly purified plasma membrane fractions. 3. 3. Plasma membrane from the white matter contained only one type of Na +K +-ATPase, whereas the gray matter plasma membrane showed two types of Na +K +-ATPase.