Structural changes of carbohydrate chains of human thyroglobulin accompanying malignant transformations of thyroid glands

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Abstract
Carbohydrate moieties were released from human thyroglobulins prepared from normal and transformed, thyroid tissues by hydrazinolysis. The oligosaccharides thus prepared were fractionated by DEAE-cellulose, Bio-Gel P-4, concanavalin-A-Sepharose and Ricinus-communis-agglutinin-Sepharose columns and were characterized by exo-glycosidase and endo-glycosidase digestions, methylation analysis and 400-MHz 1H-NMR spectroscopy. These studies showed that the alterations accompanying malignancy occurred in complex-type carbohydrate chains and exhibited the following structural features: (a) a complex-type carbohydrate chain containing 1 phosphate in a diester linkage was present in all the malignant thyroglobulins. (b) Asialo-carbohydrate chains with biosynthetically incomplete structures were found in all of the malignant thyroglobulins. (c) Carbohydrate chains of higher molecular mass, which have repeating Gal-GlcNAc disaccharides and peripheral α-fucosyl residues were present in metastatic papillary carcinoma.