The estimation of galactose, mannose and fucose in glycoproteins by radioisotope dilution

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Abstract
The principle of radio-isotope dilution, as used previously for the estimation of mannose in egg albumin, was applied on a semi -micro scale to the estimation of fucose, mannose and galactose in some glycoproteins. The sugars were separated by partition chromatography on columns of Celite 545. The release of mannose from egg albumin in 2N-hydrochloric acid at 100[degree] after various times was determined by the radioisotope-dilution method and found to have a half-time of 7 min. The destruction of mannose in 2N-hydrochloric acid after 3 hr. at 100[degree] was found to be small if air was excluded. The destruction was slightly increased by the presence of lysozyme containing tryptophan in an amount equi-molar with the mannose. The same amount of free tryptophan caused considerable loss of mannose. Analytical values are reported for the non-amino sugar contents of egg albumin, rabbit gamma-globulin and some samples of blood-group-specific substances. The values found were similar to the most reliable estimates published previously.