Topographical dissection of sheep erythrocyte membrane phospholipids by taurocholate and glycocholate.

1. Glycocholate and taurocholate removed significant amounts of membrane phospholipid from intact sheep erythrocytes before lysis of the cells occurred. The pre-lytic extract was enriched in sphingomyelin and correspondingly depleted in phosphatidylserine, phosphatidylinositol and phosphatidylethanolamine when compared to the original membrane. 2. In contrast, the phospholipid profiles of glycocholate and taurocholate extracts of unsealed ghosts, made at the same bile salt concentrations, were similar to that of the whole membrane. 3. These observations are related to the topography of the phospholipids in the membrane and to some aspects of bile formation.