Does anyone have a reference to a chemical structure of a lipid after it has undergone a non-enzymatic glycation event with glucose (or any other sugar)?
Proteins can undergo non-enzymatic glycation reactions with simple sugars. This results in advanced glycation end-product (AGE) crosslinks, glucosepane, MOLD, GOLD, DOGDIC, DODIC being some familiar ones. What are the equivalent structures for lipids?
Thanks
Dear Anthony,
The glycation end products depends on the lipid. For instance, for aminophospholipid such as glycerophosphatidylethanolamine (GPE) the amino group reacts with the carbonyl group of glucose (in aqueous solution there is always an equilibrium between the closed hemicaetal form and the open carbonyl form) forming a covalent bond. These PE-Glc adducts are more susceptible to radical damage leading to a myriad of othere secondary products. Pls have a look at (https://www.ncbi.nlm.nih.gov/pubmed/20499053). The same is true for GPS and other aminolipids.
Hope this helps.
Best regards,
Ana
Dear Ana,
That was perfect! Thank you for the reference, that is exactly what I was looking for.
Glycation is the non-enzymatic reaction between reducing sugars, such as glucose, and proteins, lipids or nucleic acids. Glycation has to be distinguished from glycosylation, which is an enzymatic reaction. Since its first description by Maillard in 1912 and its involvement in food browning during thermal processing by Hodge 50 years later, its presence in living systems and involvement in various pathologies of the human body, including aging and diabetes, have been an intensive field of research.
Formation of AGEs is a complicated molecular process involving simple and more complex multistep reactions. During the classical Maillard reaction electrophilic carbonyl groups of glucose or other reactive sugars react with free amino groups of amino acids (especially of basic lysine or arginine residues), forming a non-stable Schiff base. Further rearrangement leads to formation of a more stable ketoamine (Amadori product).Schiff bases and Amadori products are reversible reaction products. However, they can react irreversibly with amino acid residues of peptides or proteins to form protein adducts or protein crosslinks. Alternatively, they can undergo further oxidation, dehydration, polymerization and oxidative breakdown reactions to give rise to numerous other AGEs. Oxygen, reactive oxygen species (ROS) and redox active transition metals accelerate AGE formation. When an oxidative step is involved, the products are called advanced glycoxidation end products.
Dear Ana,
I hope you don't mind the further question? However, after looking at your publication record I believe you might be able to help.
Do you know of any biophysical properties of glycated lipid membrane? For example, the thickness of a glycated bilayer or its area per lipid? I have been able to find the melting phase transition from gel to liquid, however, for my purpose of deriving computational models of glycated lipids, the phase transition temperature is notorious difficult to accurately predict.
Many thanks
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