The Fluorescence Scanning of Microgels Stained for Glycoproteins with Fluorescein Isothiocyanate-Labelled Concanavalin A

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Abstract
A technique is presented which allows one to label and quantitate glycoproteins. Small amounts of protein from biological samples (0.5-2.5 .mu.g for mixtures and less for individual proteins) are separated by sodium dodecyl sulfate gel electrophoresis on 1-30% polyacrylamide gradient microgels. The gels are stained with Coomassie Brillant Blue R 250 to evaluate relative migration or fixed in 2-propanol/acetic acid and stained with fluorescein isothiocyanate-labeled concanavalin A. The microgels are then scanned using a fluorescence microscope controlled by a computer, although simpler configurations are possible. Standards of known carboxyhydrate composition (e.g., glucose oxidase) are used for comparative purposes. Glycoproteins in the order of 5-30 ng protein (or 1-5 ng carbohydrate) can be detected without difficulty. This technique may prove valuable in evaluating glycoproteins when the available material is limited.