such as "Introduction", "Conclusion"..etc
Chemical tools have been vitally important for the development of large-scale glycomics. These range from automated synthesis  to development of chemoselective coupling reactions  that facilitate attachment of oligosaccharides to arrays [35,36] and underlie high-sensitivity methods for isolating sugars from biological extracts [29,37].
Another increasingly important contribution of chemists is the
synthesis of abiotic monosaccharide analogs that are used in
oligosaccharide-engineering strategies based on metabolic substrates.
This approach exploits the unusual permissiveness of certain
biochemical pathways involved in carbohydrate biosynthesis to
accommodate non-natural metabolic intermediates .
By intercepting a targeted pathway with an analog, it is possible to
install abiotic, chemically distinct sugars into mature
glycoconjugates. The incorporation of azide-modified analogs of sialic
acid into the B-lymphocyte surface glycoprotein CD22, an important
modulator of B-lymphocyte activity, provided a recent example of this
technique's ability to discover new insights into biological roles of
glycosylation: photoaffinity cross-linking of the azide-modified sialic
acid allowed in situ identification of a potentially
important modulator of B-cell activity - previously unappreciated
homomeric binding among neighboring CD22 molecules .
An adaptation of the tagging-via-substrate (TAS) proteomics approach 
is now transforming metabolic oligosaccharide engineering into a
high-throughput technology. TAS technology involves the biosynthetic
incorporation of an azide functional group into the design of a basic
building block such as an amino acid  or monosaccharide , followed by isolation of labeled biomolecules via this chemical tag. In a pioneering study, N-azidoacetylglucosamine, an analog of GlcNAc, was used to tag O-GlcNAc-labeled proteins . The subsequent identification of around 25 O-GlcNAc-modified proteins in the brain established a biochemical link between O-GlcNAc modification and neuronal signaling, synaptic plasticity, and gene expression .
Of equal importance, this study provides a precedent for expanding the
TAS strategy to other tissues and for applying it to uncover subtle
metabolic differences between healthy and diseased cells.
Enter the code exactly as it appears. All letters are case insensitive, there is no zero.