Optimization of oxidation of glycoproteins: an assay for predicting coupling to hydrazide chromatographic supports

A rapid, simple assay for aldehydes generated by oxidation of saccharide units in glycoproteins, using dyes containing hydrazide functionalities, is described. The assay is used, in conjunction with tests of biological activity, to predict oxidation conditions that will result in a maximum of active protein coupled to a hydrazide chromatographic support. Glycoproteins are labeled with Lucifer Yellow CH or Texas Red Hydrazide, and the extent of labeling is determined. Using the assay, it is shown that the efficiency of coupling to Affi-Prep Hydrazide is proportional to oxidation.