Methylglyoxal
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{{Chembox new
|ImageFile=Methylglyoxal.png
|ImageSize=137px
|IUPACName=2-oxopropanal
|OtherNames=
|Section1= {{Chembox Identifiers
| CASNo=78-98-8
| PubChem=880
| SMILES=CC(=O)C=O
| MeSHName=Methylglyoxal
}}
|Section2= {{Chembox Properties
| Formula=C<sub>3</sub>H<sub>4</sub>O<sub>2</sub>
| MolarMass=72.0627
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
|Section3= {{Chembox Hazards
| MainHazards=
| FlashPt=
| Autoignition=
}}
}}
'''Methylglyoxal''', also called '''pyruvaldehyde''' or '''2-oxo-propanal''' (CH3-CO-CH=O or C<sub>3</sub>H<sub>4</sub>O<sub>2</sub>) is the [[aldehyde]] form of [[pyruvic acid]]. It has two [[carbonyl]] groups, so it is a [[dicarbonyl compound]]. Methylglyoxal is both an aldehyde and a [[ketone]]. Methylglyoxal is also called a ''ketal'', because it has an aldehydic and ketonic carbonyl group.
In organisms, methylglyoxal is formed as a side-product of several [[metabolic pathway]]s.<ref>{{cite journal |author=Inoue Y, Kimura A |title=Methylglyoxal and regulation of its metabolism in microorganisms |journal=Adv. Microb. Physiol. |volume=37 |issue= |pages=177–227 |year=1995 |pmid=8540421}}</ref> It may form from 3-amino [[acetone]], which is an intermediate of [[threonine]] catabolism, as well as through [[lipid peroxidation]]. However, the most important source is [[glycolysis]]. Here, methylglyoxal arises from non enzymatic phosphate elimination from glyceraldehyde phosphate en 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]] forming a hemithioacetal. This is converted into S-D-Lactoyl-Glutathione by [[glyoxalase I]],<ref>{{cite journal |author=Thornalley PJ |title=Glyoxalase I--structure, function and a critical role in the enzymatic defence against glycation |journal=Biochem. Soc. Trans. |volume=31 |issue=Pt 6 |pages=1343–8 |year=2003 |pmid=14641060 |url=http://www.biochemsoctrans.org/bst/031/1343/bst0311343.htm |doi=10.1016/S0006-2952(99)00132-X}}</ref> and then further metabolised into D-lactate by [[glyoxalase II]].<ref>{{cite journal |author=Vander Jagt DL |title=Glyoxalase II: molecular characteristics, kinetics and mechanism |journal=Biochem. Soc. Trans. |volume=21 |issue=2 |pages=522–7 |year=1993 |pmid=8359524}}</ref>
Why methylglyoxal is produced remains unknown, but several articles indicate that methylglyoxal is involved in the formation of [[advanced glycation endproduct]]s (AGEs). In fact, methylglyoxal is proven to be the most important glycation agent (forming AGEs) <ref>{{cite journal |author=Shinohara M |title=Overexpression of glyoxalase-I in bovine endothelial cells inhibits intracellular advanced glycation endproduct formation and prevents hyperglycemia-induced increases in macromolecular endocytosis. |journal=J Clin Invest. |volume=101 |issue=5 |pages=1142–7 |year=1998 |pmid=9486985 |doi=10.1172/JCI119885}}</ref>. In this process, methylglyoxal reacts with free amino groups of [[lysine]] and [[arginine]] residues of proteins forming AGEs. Other [[glycation]] agents include reducing sugars like:
*[[Glucose]], the sugar that stores [[energy]]
*[[Galactose]], a part of milk sugar ([[lactose]])
*[[Allose]], an all-cis [[hexose]] carried into the [[cell (biology)|cell]] by special [[proteins]]
*[[Ribose]], a component of [[RNA]]
==References==
{{reflist}}
[[Category:Aldehydes]]
[[Category:Ketones]]
[[Category:Metabolism]]
[[lv:Metilglioksāls]]
[[nl:Methylglyoxal]]