Studies in immunochemistry. 19. Further observations on the preparation and properties of human blood-group-specific mucopolysaccharides

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Abstract
Blood-group A-, H- and Lea-specific mucopolysaccharides, isolated from human ovarian-cyst fluids by extracting the dry cyst contents with 90% phenol, can be separated in many instances into 2 closely similar mucopolysaccharide materials by heating in saturated ammonium sulphate solution at 60[degree] for a few minutes. A part of the mucopolysaccharide preparation is precipitated and a part remains in solution. The group B-active mucopolysaccharides insoluble in 90% phenol so far examined are almost completely soluble in saturated ammonium sulphate at 60[degree]. The mucopolysaccharides insoluble or soluble in saturated ammonium sulphate at 60[degree] possess the same qualitative composition, but differ in certain physical and chemical properties. The materials insoluble under these conditions have a greater content of amino acid, are more viscous and have a larger molecular weight than have the materials soluble in ammonium sulphate, provided that the materials compared are obtained from the same cyst fluid. The mucopolysaccharides insoluble in saturated ammonium sulphate at 60[degree] are more active in hemagglutination-inhibition tests than are the ammonium sulphate-soluble materials. Group A-specific mucopolysaccharides, which are insoluble under these conditions, precipitate more antibody nitrogen from a specific antiserum than do the corresponding materials which are soluble in saturated ammonium sulphate at 60[degree]. Digestion of native cyst fluids or water-insoluble paramucinous gels with pepsin at pH 1.9, followed by treatment with saturated ammonium sulphate at 60[degree], allows blood-group substances to be recovered without the use of phenol and provides an alternative method for isolating these materials.