35] Labeling glycoconjugates with hydrazide reagents

Abstract

Publisher Summary Owing to the ubiquitous distribution of glycoconjugates and polysaccharides in nature, a variety of methods have been devised for their detection, analysis, and isolation. One of the approaches entails the initial chemical or enzymatic modification of sugars followed by subsequent interaction of the modified saccharide(s) with an appropriate probe. This chapter discusses two fundamental aldehyde-generating reactions, followed by the interaction with various hydrazides. The hydrazide reagents and probes used in these reactions are divided into radioactive, fluorescent, target, and polymeric (including enzyme) reagents. There has clearly been an increase in the use of fluorescent hydrazides compared to that of their radioactive analogs. Fluorescent hydrazides have been used to label glycoproteins, such as thyroglobulin, adenosine triphosphatase (ATPase), and for glycolipids. The labeled glycolipids have been used to examine the function of gangliosides in membranes by exogenous incorporation of the fluorescent gangliosides into the cell membrane. The chapter also discusses some illustrative labeling procedures, which include, labeling cell surface sialic acids, labeling cell surface galactose, labeling glycoproteins in solution, labeling of gangliosides, and labeling glycoconjugates on blots.