Chemistry Reference
In-Depth Information
Table 4.1
The most commonly used conjugation chemistries in neoglycoprotein synthesis.
Amino acid
Carbohydrate derivative
Reaction type
Linkage
Carboxylic acid
a
Amidation
Amide
Lysine (
ε
- NH
2
, N - terminal)
Aldehyde
Reductive amination
Amine
Ketone
Reductive amination
Amine
N
- acryloyl
Conjugate addition
Amine
Isocyanate
Ureidation
Urea
Isothiocyanate
Thioureidation
Thiourea
Imidate
Amidination
Amidine
Pseudo - thiourea
Guanidination
Guanidine
Imidazoylurethane
Carbamoylation
Carbamate
Cyanate ester
Isoureidation
Isourea
Imidocarbonate
Imidocarbonation/
carbamoylation
N
- imidocarbonate/
carbamate
Aspartic, glutamic acid,
C - terminal
Amine
Amidation
Amide
Tyrosine
Diazonium
Diazotation
Diazo
Cysteine (thiol)
Thiol
Oxidation/exchange
Disulfi de
Bromoacetyl
Substitution
Thioether
Maleimide
Conjugate addition
Thioether
N
- acryloyl
Conjugate addition
Thioether
a
Carboxylic derivatives: acyl halide, azide, hydrazide, anhydride, active ester, thiolactone.
extension of the glycan part with, for example, enzymatic-mediated glycosylation
through chemoselective ligation, has also been described. These two distinct sets
of strategies have been employed for glycoprotein remodeling and to remove
unwanted glycoforms or to link saccharide residues to proteins (for further details
on natural glycosylation, please see Chapters 6 - 8 ). Neoglycoproteins are particu-
larly useful as antibacterial vaccines (for further applications, please see Chapter
18.3 and Table 25.1 ).
4.4
Neoglycolipids and Liposomes
A generic and elegant methodology for the design of carbohydrate biosensors has
been the construction of neoglycolipids (for further details on glycolipids, please
see Chapters 10 and 30). These molecular composites, based on synthetic oligosac-
charides coupled to lipid residues, constitute interesting tools for deciphering
carbohydrate sequences and structures using microarrays. Glycolipids are found
at the surface of every cell and several hundred glycolipid structures have been
characterized on mammalian cell surfaces. Their structures differ greatly from
