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|Section2= |Section3= }} 3,4-DHSA is an organic compound which is the intermediate product of the metabolism of cholesterol, by the bacteria most commonly responsible for tuberculosis (''Mycobacterium tuberculosis'').〔; 〕 3,4-DHSA is an acronym for 3,4-dihydroxy-9,10-seco-androst-1,3,5(10)-triene-9,17-dione, the official name of this substance. It is classified as a secosteroid, since one of the four rings of cholesterol from which it is derived is broken. 3,4-DHSA is a catecholic intermediate (a compound containing an aromatic ring with two adjacent hydroxyl groups) produced by ''M. tuberculosis'' during the break down of cholesterol.〔 3,4-DHSA is also produced by other bacteria such as ''Comamonas testosteroni''. A particular type of enzyme known as extradiol dioxygenase is responsible for the oxidation and ring opening of 3,4-DHSA to 4,9-DSHA (see metabolic scheme below). ''M. tuberculosis'' bacteria that are deficient in this enzyme are less lethal than wild-type bacteria. 3,4-DHSA itself appears to be toxic to the bacteria while the breakdown products of 3,4-DHSA can be used as energy source by the bacteria. Hence blocking the oxidation of 3,4-DHSA by the extradiol dioxygenase enzyme may be useful in the treatment of tuberculosis.〔 A crystal structure of DHSA in complex with ''M. tuberculosis'' iron-dependent extradiol dioxygenase has been determined.〔 ==References== 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「DHSA」の詳細全文を読む スポンサード リンク
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