Structure determination of the carbohydrate chains of rat α‐fetoprotein

Abstract

By affinity chromatography on concanavalin A (ConA) linked to Sepharose, S-carboxymethylated rat .alpha.-fetoprotein could be separated into 2 molecular variants: a ConA-reactive and a ConA-nonreactive fraction. The carbohydrate chains were quantitatively released from the protein by hydrazinolysis. Based on methylation analysis and high-resolution 1H-NMR spectroscopy of the re-N-acetylated hydrazinolysates, the carbohydrate structures of the 2 ConA-molecular variants of .alpha.-fetoprotein were established. The ConA-reactive species contains 2 N-glycosidic carbohydrate units/molecule, both having the same structure. The ConA-nonreactive species possesses also 2 N-glycosidically linked oligosaccharide chains per molecule with identical structures that are different from those of the ConA-reactive species.