Determination of L-Fucose in Glycoproteins. I. Effect of Nonfucose Moieties of Serum Glycoproteins

Abstract : The effect of galactose, mannose, and tryptophan on the determination of the methylpentose L-fucose in glycoproteins by the cysteine-sulfuric acid reaction is described. Under certain analytical conditions, protein-bound hexoses significantly contribute to the apparent fucose level. The true fucose level may be approximated under these same conditions by means of an empirically derived equation relating the concentration of serum protein-bound hexoses to the true fucose level. Fucose levels obtained with pathological and nonpathological sera by various methods are compared and specific conditions for the reliability of the statistics are defined and discussed.