Cattle blood group J Glycolipid II. Quantitative and structural study of J active glycolipid

Abstract

J active lipid was isolated from bovine J cs serum, and the chemical structure of the lipid was investigated by chemical and enzymatic degradation and analysis. Deacylation by mild alkaline methanolysis of the J active lipid liberated the O-acyl-linked fatty acids which were identified as stearate, isostearate and palmitate. The deacylated lipid contained long-chain base, glucose, galactose, fatty acids, phosphorus and glycerol. Studies with d-galactose oxidase showed that the galactose in the intact active J lipid and in the deacylated lipid was not oxidized by this enzyme, but the galactose in the trihexoside ceramide isolated from the J active lipid was oxidized by the enyzme. This suggests that the galactose is blocked or is non-terminal in the intact lipid and in the deacylated lipid and is terminal in the ceramide trihexoside. The active J lipid is inactivated by exposure to phospholipase C, indicating the presence of phosphate diester. On the basis of this information and earlier published data, the following structure is tentatively suggested for the J active lipid: ▪ The exact placement of the bracketed phosphate moiety has not been determined.