Biochemistry of the Sphingolipids

Hydrolysis of phytoglycolipid by barium hydroxide yielded the various products possible from cleavage of the phosphate diester bond (ceramide phosphate plus oligosaccharide and ceramide plus oligosaccharide phosphate). About 50% of the oligosaccharide was recovered as a phosphorus-free, amorphous solid, the analytical data for which suggested a hexasaccharide structure. Studies on the fractionation of this mixture will be presented in a subsequent publication. It is the purpose of this report to present degradation studies on the crude oligosaccharide which have provided substantial additional evidence as to the basic structures involved. In a previous communication (3), it was shown that crude oligosaccharide on mild acid degradation yields a relatively stable trisaccharide containing inositol, glucosamine, and hexuranic acid. This material is obtained in excellent yields as a crystalline product which accounts for essentially all of the glucosamine and hexuronic acid of the oligosaccharides. Since this unit constitutes a common moiety present in PGLr from a