Observations on the structure of the barium salt of heparin

Abstract

Various methods are descr. for the prep. of a crystalline Ba salt of heparin. The Ba salt, isolated from various tissues (liver, lung and intestine), is identical in properties and is a chemical individual. By treatment with acidified methyl alcohol under varying conditions heparin yields a series of products of lower physiological activity, decrease in activity being accompanied by a decrease in sulphur content. Material completely inactivated in this way appears to have undergone structural alteration in addition to removal of sulphate groupings. The structure of heparin is discussed; it is a mucoitin sulphuric acid in which the basic tetrasaccharide unit contains 5 sulphuric ester groupings. Analyses of the Ba salt and of the NH4 salt prepd. from it are in agreement with this view. In the Ba salt the carboxyl groups are probably unsubstituted.