Formula C3H4O2 Density 1.046 g/cm³ Appearance Yellow liquid | Molar mass 72.06266 g/mol Boiling point 72 °C | |
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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.
Contents
Industrial production and use
Methylglyoxal is produced industrially by degradation of carbohydrates using overexpressed methylglyoxal synthase.
Biochemistry
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.
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. 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:
Natural occurrence
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 and is the dominant antibacterial constituent. However, after neutralization of this compound, manuka honey retains bactericidal activity. implying that there are other contributors to the antimicrobial and antibacterial activities.