|Molar mass||72.06 g·mol−1|
|Boiling point||72 °C (162 °F; 345 K)|
Except where noted otherwise, data is 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 reduced derivative of pyruvic acid.
Industrial production and use
Methylglyoxal is produced industrially by degradation of carbohydrates using overexpressed methylglyoxal synthase. It is reduced (hydrogenation) either to 2-hydroxyacetone or to lactaldehyde, depending on the carbonyl group that is reduced. Further reduction affords propylene glycol, a useful diol in the production of polyesters.
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, the body developed several detoxification mechanisms. One of these is the glyoxalase system. Methylglyoxal reacts with glutathione to form a hemithioacetal. This is converted into S-D-lactoyl-glutathione by glyoxalase I, and then further metabolized into D-lactate by glyoxalase II.
Why methylglyoxal is produced remains 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. Recent research has identified heat shock protein 27 (Hsp27) as a specific target of posttranslational modification by methylglyoxal in human metastatic melanoma cells.
Recently one mechanism of activity in humans of methylglyoxal has been identified. Methylglyoxal binds directly to the nerve endings and by that increases the chronic extremity soreness in diabetic neuropathy.
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 an active component of manuka honey. However, after neutralization of this compound manuka honey retains bactericidal activity due to unknown factors. Methylglyoxal can not be directly linked and stated as the main content to the antimicrobial and antibacterial activities in manuka honey 
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