3D model (JSmol)
|Molar mass||g·mol−1 72.063|
|Boiling point||72 °C (162 °F; 345 K)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Methylglyoxal, also called pyruvaldehyde or 2-oxopropanal, is the organic compound with the formula CH3C(O)CHO. Gaseous methylglyoxal has two carbonyl groups, an aldehyde and a ketone but in the presence of water, it exists as hydrates and oligomers. It is a reduced derivative of pyruvic acid.
Industrial production and biosynthesis
In organisms, methylglyoxal is formed as a side-product of several metabolic pathways. It may form from 3-aminoacetone, which is an intermediate of threonine catabolism, as well as through lipid peroxidation. However, the most important source is glycolysis. Here, methylglyoxal arises from nonenzymatic phosphate elimination from glyceraldehyde phosphate and dihydroxyacetone phosphate, two intermediates of glycolysis.
Since methylglyoxal is highly cytotoxic, several detoxification mechanisms have evolved. One of these is the glyoxalase system. Methylglyoxal is detoxified by glutathione. Glutathione reacts with methylglyoxal to give a hemithioacetal, which converted into S-D-lactoyl-glutathione by glyoxalase I. This thioester is hydrolyzed to D-lactate by glyoxalase II.
The proximate and ultimate causes for biological methylglyoxal production remain unknown, but it may be involved in the formation of advanced glycation endproducts (AGEs). In this process, methylglyoxal reacts with free amino groups of lysine and arginine and with thiol groups of cysteine forming AGEs. The heat shock protein 27 (Hsp27) is a specific target of posttranslational modification by methylglyoxal in human metastatic melanoma cells.
Other glycation agents include the reducing sugars:
- glucose, the sugar that stores energy
- galactose, a component of milk sugar (lactose)
- allose, an all-cis hexose carried into the cell by special proteins
- ribose, a component of RNA.
Due to increased blood glucose levels, methylglyoxal has higher concentrations in diabetics and has been linked to arterial atherogenesis. Damage by methylglyoxal to low-density lipoprotein through glycation causes a fourfold increase of atherogenesis in diabetics.
Although methylglyoxal has been shown to increase carboxymethyllysine levels, methylglyoxal has been suggested to be a better marker for investigating the association between AGEs with adverse health outcomes.
Methylglyoxal is a component of some kinds of honey, including manuka honey; it appears to have activity against E. coli and S. aureus and may help prevent formation of biofilms formed by P. aeruginosa .
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