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In enzymology, a lactoylglutathione lyase () (also known as glyoxalase I) is an enzyme that catalyzes the isomerization of hemithioacetal adducts, which are formed in a spontaneous reaction between a glutathionyl group and aldehydes such as methylglyoxal. :glutathione + methylglyoxal hemithioacetal adduct (R)-S-lactoylglutathione Glyoxalase I derives its name from its catalysis of the first step in the glyoxalase system, a critical two-step detoxification system for methylglyoxal. Methylglyoxal is produced naturally as a byproduct of normal biochemistry, but is highly toxic, due to its chemical reactions with proteins, nucleic acids, and other cellular components. The second detoxification step, in which (R)-S-lactoylglutathione is split into glutathione and D-lactate, is carried out by glyoxalase II, a hydrolase. Unusually, these reactions carried out by the glyoxalase system does not oxidize glutathione, which usually acts as a redox coenzyme. Although aldose reductase can also detoxify methylgloxal, the glyoxalase system is more efficient and seems to be the most important of these pathways. Glyoxalase I is an attractive target for the development of drugs to treat infections by some parasitic protozoa, and cancer. Several inhibitors of glyoxalase I have been identified, such as S-(N-hydroxy-N-methylcarbamoyl)glutathione. Glyoxalase I is classified as a carbon-sulfur lyase although, strictly speaking, the enzyme does not form or break a carbon-sulfur bond. Rather, the enzyme shifts two hydrogen atoms from one carbon atom of the methylglyoxal to the adjacent carbon atom. In effect, the reaction is an intramolecular redox reaction; one carbon is oxidized whereas the other is reduced. The mechanism proceeds by subtracting and then adding protons, forming an enediolate intermediate, rather than by transferring hydrides. Unusually for a metalloprotein, this enzyme shows activity with several different metals. Glyoxalase I is also unusual in that it is stereospecific in the second half of its mechanism, but not in the first half. Structurally, the enzyme is a domain-swapped dimer in many species, although the two subunits have merged into a monomer in yeast, through gene duplication. == Nomenclature == The systematic name of this enzyme class is (R)-S-lactoylglutathione methylglyoxal-lyase (isomerizing glutathione-forming); other names include ''methylglyoxalase'', ''aldoketomutase'', ''ketone-aldehyde mutase'', and ''(R)-S-lactoylglutathione methylglyoxal-lyase (isomerizing)''. In some instances, the glutathionyl moiety may be supplied by trypanothione, the analog of glutathione in parasitic protozoa such as the trypanosomes. The human gene for this enzyme is called GLO1. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lactoylglutathione lyase」の詳細全文を読む スポンサード リンク
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