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|Section2= |Section3= |Section4= }} Malondialdehyde (MDA) is the organic compound with the formula CH2(CHO)2. The structure of this species is more complex than this formula suggests. This reactive species occurs naturally and is a marker for oxidative stress. == Structure and synthesis == Malondialdehyde mainly exists in the enol form:〔V. Nair, C. L. O'Neil, P. G. Wang "Malondialdehyde", ''Encyclopedia of Reagents for Organic Synthesis'', 2008, John Wiley & Sons, New York. Article Online Posting Date: March 14, 2008〕 :CH2(CHO)2 → HOCH=CH-CHO In organic solvents, the ''cis''-isomer is favored, whereas in water the ''trans''-isomer predominates. Malondialdehyde is a highly reactive compound that is not typically observed in pure form. In the laboratory it can be generated in situ by hydrolysis of 1,1,3,3-tetramethoxypropane, which is commercially available.〔 It is easily deprotonated to give the sodium salt of the enolate (m.p. 245 °C). Malondialdehyde results from lipid peroxidation of polyunsaturated fatty acids. It is a prominent product in Thromboxane A2 synthesis wherein cyclooxygenase 1 or cycloxygenase 2 metabolizes arachidonic acid to prostaglandin H2 by platelets and a wide array of other cell types and tissues. This product is further metabolized by Thromboxane synthase to Thromboxane A2, 12-Hydroxyheptadecatrienoic acid, and malonyldialdehyde.〔J. Biol. Chem. 248:5673; 1973〕〔Proc. Natl. Acad. Sci. USA 71:3400; 1974〕 Alternatively, it may rearrange non-enzymatically to a mixture of 8-cis and 8-trans isomers of 12-hydroxyeicosaheptaenoic acid plus malonyldialdehyde (see 12-Hydroxyheptadecatrienoic acid).〔Prostaglandins Other Lipid Mediat. 1998 Jun;56(2-3):53-76〕 The degree of lipid peroxidation can be estimated by the amount of malondialdehyde in tissues.〔 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「Malondialdehyde」の詳細全文を読む スポンサード リンク
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