Increased selectivity in the detection of glycoproteins on nitrocellulose membranes by washing with sodium hydroxide solution.

We increased selectivity in the detection of glycoproteins on nitrocellulose membranes by introducing a washing step using sodium hydroxide solution. Glycoproteins on the nitrocellulose membrane were first oxidized by sodium periodate; biotin hydrazide was then coupled to the aldehyde groups generated in the sugar moiety of the glycoproteins. The membrane was washed twice using sodium hydroxide solution, and avidin-horseradish peroxidase was then coupled to the remaining biotin. This system allows the detection of nanograms of glycoproteins on nitrocellulose membranes, and its specificity allows the clear distinction of glycoproteins from the nonglycosylated protein of bovine serum albumin.