Glycomics: A complex challenge

Abstract

At a time when the sequencing of genomes is becoming trivial, defining the proteome by proteomics is causing more difficulties; however, the real challenge will be the study of the co- and posttranslational modifications of these proteins. Among these, the study of glycosylation will be the most challenging owing to the chemical nature of glycans. These are built on several monosaccharide types that can be linked together at different linkage positions with two linkage configurations ( and ), and finally, more than one sugar can be attached to one monosaccharide unit, which give rise to branching. Over the years, the various ways that two monosaccharides can be linked together have been discussed, although this is a theoretical exercise that has limited practical meaning as the number of actual linkage positions and configurations used is much less and is limited by the specificities of the glycosyltransferases, the enzymes that are responsible for the biosynthesis of glycans.