Glycation (or glycation) is a non-enzymatic process in which sugar molecules (such as glucose, fructose, or galactose) bind to proteinsProteins are high-molecular organic substances consisting of alpha-amino acids linked in a chain by a peptide bond. In living organisms, the amino acid composition of proteins is determined by the genetic code. During synthesis, 20 standard amino acids are used in most cases. Many combinations of them determine the great diversity of properties of protein molecules. Proteins play a key role in the immune response and can perform transport, storage, catalytic, structural, and receptor functions. Proteins are an important part of the nutrition of animals and humans. The main sources of proteins are meat, poultry, fish, milk, nuts, legumes, and grains., lipids, or nucleic acids to form stable compounds. This process plays an important role in biology and medicine, as it can affect the structure and function of molecules, as well as participate in the development of various diseases, including diabetes, aging and neurodegenerative disorders.
Main stages of glycation
Initial stage (Schiff base formation):
A sugar molecule (for example, glucose) interacts with the free amino group (NH₂) of a protein (for example, lysineLysine is an essential amino acid that is one of the main components of protein molecules with pronounced basic properties. In DNA, it is encoded by the sequences AAA and AAG. It is the foundation that makes up protein — the building material for the body's cells and tissues. The body cannot produce lysine on its own; the amino acid enters it with food or through taking special supplements. or arginine), forming an unstable compound — the Schiff base.
This is a reversible reaction that can occur both in the forward and reverse directions.
Amadori stage (formation of ketosamines):
The Schiff base undergoes a rearrangement, turning into a more stable compound — ketosamine (for example, fructosamine).
This stage is also reversible, but less dynamic.
Formation of glycation end-products (AGEs, Advanced Glycation End-products):
Ketosamines can undergo further chemical transformations, including oxidation, dehydration, and polymerization.
As a result, glycation end products (AGEs) are formed, which are stable and irreversible compounds.
AGEs can accumulate in tissues and organs, causing damage.
The role of glycation in the body
Glycation is a natural process that occurs in the body all the time. However, when blood sugar levels are elevated (such as in diabetes), this process is accelerated, which leads to the accumulation of AGEs and tissue damage.
Effect on proteins
Structural changes: Glycation can alter the structure of proteins, making them less functional. For example, glycation of collagenCollagen is a fibrillar protein, one of the main building elements of the body. It constitutes a significant part of connective tissues such as skin, tendons, joints, bones, and cartilage. Collagen provides strength, elasticity, and structural integrity to these tissues, giving them the ability to resist stretching. (the main protein of connective tissue) leads to a loss of elasticity of the skin and blood vessels.
Functional changes: Glycation of enzymesEnzymes are proteins that accelerate chemical reactions in the body. They ensure the occurrence of metabolic processes such as food digestion, energy release, cell formation, and many others. can reduce their activity, and glycation of receptors can disrupt signal transmission.
Effect on lipids
Glycation of lipids can change the properties of cell membranes, making them more rigid and less permeable.
Effects on DNA
DNA glycation can lead to mutations and disruption of DNA repair processes.
Pathological consequences of glycation
Diabetes:
In diabetes, elevated blood glucose levels accelerate the glycation process.
Accumulation of AGEs in blood vessels, kidneys, nerves, and eyes leads to the development of complications such as diabetic retinopathy, nephropathy, and neuropathy.
Aging:
With age, the level of AGEs in the body increases, which contributes to the aging of tissues.
Glycation of collagen and elastin leads to loss of skin elasticity, the appearance of wrinkles and deterioration of vascular function.
Neurodegenerative diseases:
The accumulation of AGEs in the brain is associated with the development of Alzheimer’s and Parkinson’s diseases.
Glycation of proteins such as tau protein and amyloid beta can contribute to the formation of amyloid plaques.
Cardiovascular diseases:
Glycation of vascular wall proteins leads to an increase in arterial stiffness and the development of atherosclerosis.
Mechanisms of protection against glycation
The body has several mechanisms to protect itself from the harmful effects of glycation:
Enzymatic degradation of AGEs:
Some enzymes, such as fructosamine-3-kinase, can break down early glycation products.
Antioxidants:
Antioxidants (such as vitamin C and vitamin E) help prevent oxidative processes that contribute to the formation of AGEs.
AGEs (RAGE)receptors:
These receptors bind AGEs and promote their removal from the body. However, if there is an excess of AGEs, RAGE activation can lead to inflammation and tissue damage.
Prevention and treatment
To reduce the negative impact of glycation, it is recommended to:
Control of blood sugar levels (especially in diabetic patients).
Follow a diet low in simple sugars.
Eating foods rich in antioxidants (vegetables, fruits, nuts).
Use of drugs that inhibit the formation of AGEs (for example, aminoguanidine).
Conclusion
Glycation is an important biochemical process that plays a key role in the development of many diseases. Understanding its mechanisms allows us to develop new approaches to the prevention and treatment of diabetes, aging, and other pathologies. Blood sugar control and a healthy lifestyle remain the main ways to reduce the negative effects of glycation on the body.
