Pentosidine
Encyclopedia
Pentosidine is a biomarker for advanced glycation endproduct
s, or AGEs. It is a well characterized and easily detected member of this large class of compounds.
and hyperglycemia
. They serve as markers of stress and act as toxins themselves. Pentosidine is typical of the class, except that it fluoresces
, which allows it to be seen and measured easily. Because it is well characterized, it is often studied to provide new insight into the biochemistry of AGE compounds in general.
, a pentose
, pentosidine forms fluorescent cross-links between the arginine
and lysine
residues in collagen
. It is formed in a reaction of the amino acids with the Maillard reaction
products of ribose.
Although it is present only in trace concentrations among tissue proteins, it is useful for assessing cumulative damage to
proteins—advanced glycation endproduct
s—by non-enzymatic browning reactions with carbohydrate
s.
, pentosidine correlates with the presence and severity of diabetic complications.
Advanced glycation endproduct
An advanced glycation end-product is the result of a chain of chemical reactions after an initial glycation reaction. The intermediate products are known, variously, as Amadori, Schiff base and Maillard products, named after the researchers who first described them. An advanced glycation...
s, or AGEs. It is a well characterized and easily detected member of this large class of compounds.
Background
AGEs are biochemicals formed continuously under normal circumstances, but more rapidly under a variety of stresses, especially oxidative stressOxidative stress
Oxidative stress represents an imbalance between the production and manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage...
and hyperglycemia
Hyperglycemia
Hyperglycemia or Hyperglycæmia, or high blood sugar, is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a glucose level higher than 13.5mmol/l , but symptoms may not start to become noticeable until even higher values such as 15-20 mmol/l...
. They serve as markers of stress and act as toxins themselves. Pentosidine is typical of the class, except that it fluoresces
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
, which allows it to be seen and measured easily. Because it is well characterized, it is often studied to provide new insight into the biochemistry of AGE compounds in general.
Biochemistry
Derived from riboseRibose
Ribose is an organic compound with the formula C5H10O5; specifically, a monosaccharide with linear form H––4–H, which has all the hydroxyl groups on the same side in the Fischer projection....
, a pentose
Pentose
A pentose is a monosaccharide with five carbon atoms. Pentoses are organized into two groups. Aldopentoses have an aldehyde functional group at position 1...
, pentosidine forms fluorescent cross-links between the arginine
Arginine
Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...
and lysine
Lysine
Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....
residues in collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
. It is formed in a reaction of the amino acids with the Maillard reaction
Maillard reaction
The Maillard reaction is a form of nonenzymatic browning similar to caramelization. It results from a chemical reaction between an amino acid and a reducing sugar, usually requiring heat....
products of ribose.
Although it is present only in trace concentrations among tissue proteins, it is useful for assessing cumulative damage to
proteins—advanced glycation endproduct
Advanced glycation endproduct
An advanced glycation end-product is the result of a chain of chemical reactions after an initial glycation reaction. The intermediate products are known, variously, as Amadori, Schiff base and Maillard products, named after the researchers who first described them. An advanced glycation...
s—by non-enzymatic browning reactions with carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
s.
Physiology
In vivo, AGEs form pentosidine through sugar fragmentation. In patients with Diabetes mellitus type 2Diabetes mellitus type 2
Diabetes mellitus type 2formerly non-insulin-dependent diabetes mellitus or adult-onset diabetesis a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and...
, pentosidine correlates with the presence and severity of diabetic complications.