Pentosidine is a biomarker for
advanced glycation endproductAdvanced Glycation End products are 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. Advanced Glycation End products...
s, or AGEs. It is a well characterized and easily detected member of this large class of compounds.
AGEs are biochemicals formed continuously under normal circumstances, but more rapidly under a variety of stresses, especially
oxidative stressOxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage. All forms of life maintain a reducing environment within their cells...
and
hyperglycemiaHyperglycemia, hyperglycaemia, or high blood sugar is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood glucose level of 10+ mmol/L , but symptoms may not start to become noticeable until later numbers such as 15-20+ mmol/L or...
. They serve as markers of stress and act as toxins themselves. Pentosidine is typical of the class, except that it
fluorescesFluorescence is the emission of visible light by a substance that has absorbed light of a differing, usually invisible, wavelength. Absorption of a photon triggers the emission of a photon with a longer wavelength. A shorter wavelength emission is sometimes observed from multiple photon absorption...
, which allows it to be seen and measured easily.
Pentosidine is a biomarker for
advanced glycation endproductAdvanced Glycation End products are 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. Advanced Glycation End products...
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 is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage. All forms of life maintain a reducing environment within their cells...
and
hyperglycemiaHyperglycemia, hyperglycaemia, or high blood sugar is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood glucose level of 10+ mmol/L , but symptoms may not start to become noticeable until later numbers such as 15-20+ mmol/L or...
. They serve as markers of stress and act as toxins themselves. Pentosidine is typical of the class, except that it
fluorescesFluorescence is the emission of visible light by a substance that has absorbed light of a differing, usually invisible, wavelength. Absorption of a photon triggers the emission of a photon with a longer wavelength. A shorter wavelength emission is sometimes observed from multiple photon absorption...
, 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, primarily occurring as
D-ribose, is an organic compound that occurs widely in nature. It is an aldopentose, that is a monosaccharide containing five carbon atoms that, in its acyclic form, has an aldehyde functional group at one end. This species predominantly exists in the...
, a
pentoseA pentose is a monosaccharide with five carbon atoms.They either have an aldehyde functional group in position 1 , or a ketone functional group in position 2 ....
, pentosidine forms fluorescent cross-links between the
arginineArginine is an α-amino acid. The
L-form is one of the 20 most common natural amino acids. Its codons are CGU, CGC, CGA, CGG, AGA, and AGG. In mammals, arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health...
and
lysineLysine is an α-amino acid with the chemical formula HO
2CCH
4NH
2. This amino acid is an essential amino acid, which means that humans cannot synthesize it. Its codons are AAA and AAG.Lysine is a base, as are arginine and histidine...
residues in
collagenCollagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content. It is naturally found exclusively in metazoa, including sponges. In muscle tissue it serves as a major component of endomysium...
. It is formed in a reaction of the amino acids with the
Maillard reactionThe Maillard reaction is a chemical reaction between an amino acid and a reducing sugar, usually requiring heat. It is vitally important in the preparation or presentation of many types of food, and, like caramelization, it is a form of non-enzymatic browning...
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 endproductAdvanced Glycation End products are 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. Advanced Glycation End products...
s—by non-enzymatic browning reactions with
carbohydrateCarbohydrates
[Means "hydrates of carbon"] or saccharides
[The word comes from the Greek σάκχαρον, sákcharon, meaning "sugar").] are the most abundant of the four major classes of biomolecules...
s.
Physiology
In vivo, AGEs form pentosidine through sugar fragmentation. In patients with
Diabetes mellitus type 2Diabetes mellitus type 2 or type 2 diabetes is a disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency...
, pentosidine correlates with the presence and severity of diabetic complications.