Fatty acid composition of total lipids and phospholipids of membrane preparations of transport ATPases

: The fatty acid composition of total lipids and phospholipids of duck salt gland Na,K-ATPase (outer plasma membrane) and of rabbit skeletal muscle Ca-ATPase (intracellular membrane) was investigated. The bulk of Na,K-ATPase fatty acids is represented by palmitic (16:0), oleic (18:1), stearic (18:0) and arachidonic (20:4) acids. The duck salt gland is characterized by rather a high content of unsaturated fatty acids, especially of arachidonic acid. The unsaturation index of total-lipid fatty acids increases during purification of these preparations in the following order: homogenate greater than microsomal fraction greater than purified enzyme. The fatty acid composition of Na,K-ATPase total lipids and phospholipids reveals certain differences. Phospholipids contain more stearic and liholeic (18:2) acids than total lipids, but the level of arachidonic acid in them is twice as low. Besides, phospholipids were found to contain polyunsaturated docosohexaenic (22:6) acid. The bulk of fatty acids of rabbit skeletal muscle Ca-ATPase total lipids and phospholipids is represented by 16:0, 18:0, 18:1 and 18:2 acids. The content of polyunsaturated fatty acids in this preparation is much lower than in duck salt gland Na,K-ATPase. The fatty acid composition of total lipids and phospholipids in rabbit skeletal muscle Ca-ATPase differ insignificantly. The differences in the fatty acid composition of membrane preparations under study is conditioned mainly by the fractional composition of their lipids.