Influence of Preparative Method on the Lipid Profiles of Bovine Fat Globule Membrane

The lipid profiles of bovine fat globule membrane preparations were obtained using a procedure that separates neutral and polar lipids on a silica cartridge. analyzes components of these two lipid groups by high performance liquid chromatography, and identifies fatty acids of total lipid as well as neutral and polar lipids separately by gas chromatography. Fat globule membrane preparation involved either churning the cream, followed by ammonium sulfate precipitation of membrane, or a combined isolation-extraction with dimethyl sulfoxide. In preparations that did not include a delipidation step. the carryover of neutral lipids was significant. In contrast, preparations that were delipidated after ammonium sulfate precipitation or as part of the isolation-extraction had much lower levels of neutral lipids. For the latter samples, values for neutral and polar lipids were comparable to those reported previously. The relative ease with which fat globule membrane is obtained using the isolation-extraction procedure makes it the preferred method for subsequent isolation and purification of fat globule membrane proteins.