Abstract
The scientific field of glycobiology comprises a
broad area of research. What unites all the
researchers in this field is the study of the structure,
biosynthesis, and biological functions of saccharides.
Of these a tremendous amount of research has been
done on glycoconjugates which refers to all types of
biological molecule that link to some saccharides.
Among these glycoconjugates are the glycoproteins
found in vivo. The glycosylation of proteins is an
enzymatic biochemical process that attachs
saccharides covalently to amino acids. It leads to
post-translational modifications of proteins which are
often crucial for the functionality of such
glycoproteins. Another type of glycoprotein is
formed by the Maillard reaction, also called
glycation. In this case enzymes are not involved in
the modification of proteins but rather it is random
chemical reactions that are concerned. Due to their
chemical properties lysine and arginine are the main
targets of glycation on proteins. In mammalian
tissues and cells, the main saccharides which react
with amino acids are sugars with a reducing function,
such as glucose, ribose and glyceraldehyde. Despite
their low concentration in vivo, oxoaldehydes play a
significant role in glycation due to their high
chemical reactivity on amino groups. Endogenous
glycation often disturbs not only the structure but
also the function of proteins and in turn affect the
functioning of organs and tissues during ageing,
kidney failure and metabolic disorders. This keynote
lecture will summarize the ongoing research on
glycation with a specific focus on the exposure to
dietary glycated proteins (exogenous glycation) and
its health consequences.
Keywords
Biochemistry, Glycation
Glycation is the most general term describing the adduction of a carbohydrate to another biomolecule, such as a protein, lipid, or DNA. Glycation may occur either enzymatically or nonenzymatically. The common term for enzymatic glycation is glycosylation, for example, formation of a glycosidic bond using a sugar nucleotide donor during synthesis of glycoproteins. The terms nonenzymatic glycation, nonenzymatic glycosylation, or glycation (without a modifier) are commonly used in reference to direct chemical reactions of reducing sugars with proteins, illustrated by the reaction of glucose with lysine residues in protein to form a ketoamine (Amadori) adduct). Glucation, fructation, ribation, etc. are used in reference to glycation by specific sugars.
Glycation is the covalent attachment of a sugar to a protein or lipid. Typical sugars that participate in glycation are glucose, fructose, and their derivatives. Glycation is the non-enzymatic process responsible for many complications in diabetes mellitus and is implicated in some diseases and in aging.
