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1-4-dihydroxy-2-napthoate (DHNA) polyprenyltransferase (EC (2.5.1.74 )) is an enzyme that catalyzes the chemical reaction: all-trans-nonaprenyl diphosphate + 1-4-dihydroxy-2-napthoate + H+ -9 + diphosphate + carbon dioxide Hence, the 3 substrates of this enzyme are all-trans-nonaprenyl diphosphate, 1-4-dihydroxy-2-napthoate, and a hydrogen ion, and the three products are -9, diphosphate, and carbon dioxide. However, other substrates this enzyme can use include farnesyl diphosphate or solanesyl diphosphate in replacement of all-trans-nonaprenyl diphosphate. 1-4-dihydroxy-2-napthoate polyprenyltransferase is located at 88 min on the ''E. coli'' chromosome while the rest of the genes responsible for the synthesis of menaquinone (Vitamin K) are clustered at 51 min.〔 This enzyme belongs to the transferase family, specifically transferring alkyl or aryl groups other than methyl groups. Other names for the enzyme include 1-4-dihydroxy-2-napthoate octaprenyltransferase, 1-4-dihydroxy-2-napthoate monoprenyltransferase, and MenA.〔 == Function == 1-4-dihydroxy-2-napthoate polyprenyltransferase is the 8th out of 9 steps in the biosynthesis of menaquinone (Vitamin K), specifically -9 within ecoli. Vitamin K is a cofactor vital for living and functions as one electron transporter in photosynthesis as a redox molecule. The reactions this enzyme catalyzes works by taking the soluble bicyclic naphthalenoid compound DHNA and converting it into -9 by attaching a 40 carbon side chain to DHNA. However this enzyme is unique in the sense that it can put different lengths of carbon side chains onto DHNA to produce different and menaquinols. Other organisms that contain this pathway include ''Micrococcus luterus'' and ''Mycobacterium tuberculosis''.〔 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「1,4-dihydroxy-2-naphthoate polyprenyltransferase」の詳細全文を読む スポンサード リンク
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