Hoeffler Jean-François, Hemmerlin Andréa, Grosdemange-Billiard Catherine, Bach Thomas J, Rohmer Michel
Université Louis Pasteur/CNRS, Institut Le Bel, 4 rue Blaise Pascal, 67070 Strasbourg cedex, France.
Biochem J. 2002 Sep 1;366(Pt 2):573-83. doi: 10.1042/BJ20020337.
In the bacterium Escherichia coli, the mevalonic-acid (MVA)-independent 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway is characterized by two branches leading separately to isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The signature of this branching is the retention of deuterium in DMAPP and the deuterium loss in IPP after incorporation of 1-[4-(2)H]deoxy-d-xylulose ([4-(2)H]DX). Feeding tobacco BY-2 cell-suspension cultures with [4-(2)H]DX resulted in deuterium retention in the isoprene units derived from DMAPP, as well as from IPP in the plastidial isoprenoids, phytoene and plastoquinone, synthesized via the MEP pathway. This labelling pattern represents direct evidence for the presence of the DMAPP branch of the MEP pathway in a higher plant, and shows that IPP can be synthesized from DMAPP in plant plastids, most probably via a plastidial IPP isomerase.
在大肠杆菌中，不依赖甲羟戊酸（MVA）的2-C-甲基-D-赤藓糖醇-4-磷酸（MEP）途径的特点是有两个分支，分别通向异戊烯基二磷酸（IPP）和二甲基烯丙基二磷酸（DMAPP）。这种分支的特征是在掺入1-[4-(2)H]脱氧-D-木酮糖（[4-(2)H]DX）后，DMAPP中保留氘而IPP中氘丢失。用[4-(2)H]DX饲喂烟草BY-2细胞悬浮培养物后，通过MEP途径合成的质体类异戊二烯、八氢番茄红素和质体醌中，源自DMAPP以及IPP的异戊二烯单元中都保留了氘。这种标记模式是高等植物中存在MEP途径的DMAPP分支的直接证据，表明IPP可能在植物质体中由DMAPP合成，很可能是通过质体IPP异构酶。
