Rohmer M, Knani M, Simonin P, Sutter B, Sahm H
Ecole Nationale Supérieure de Chimie de Mulhouse, France.
Biochem J. 1993 Oct 15;295 ( Pt 2)(Pt 2):517-24. doi: 10.1042/bj2950517.
Incorporation of 13C-labelled glucose, acetate, pyruvate or erythrose allowed the determination of the origin of the carbon atoms of triterpenoids of the hopane series and/or of the ubiquinones from several bacteria (Zymomonas mobilis, Methylobacterium fujisawaense, Escherichia coli and Alicyclobacillus acidoterrestris) confirmed our earlier results obtained by incorporation of 13C-labelled acetate into the hopanoids of other bacteria and led to the identification of a novel biosynthetic route for the early steps of isoprenoid biosynthesis. The C5 framework of isoprenic units results most probably (i) from the condensation of a C2 unit derived from pyruvate decarboxylation (e.g. thiamine-activated acetaldehyde) on the C-2 carbonyl group of a triose phosphate derivative issued probably from dihydroxyacetone phosphate and not from pyruvate and (ii) from a transposition step. Although this hypothetical biosynthetic pathway resembles that of L-valine biosynthesis, this amino acid or its C5 precursors could be excluded as intermediates in the formation of isoprenic units.
掺入13C标记的葡萄糖、乙酸盐、丙酮酸或赤藓糖，可以确定来自几种细菌（运动发酵单胞菌、藤泽甲基杆菌、大肠杆菌和嗜酸嗜热栖热菌）的藿烷系列三萜类化合物和/或泛醌的碳原子来源，这证实了我们早期通过将13C标记的乙酸盐掺入其他细菌的藿烷类化合物中所获得的结果，并导致了类异戊二烯生物合成早期步骤的一条新生物合成途径的鉴定。异戊烯单元的C5骨架很可能（i）源于丙酮酸脱羧产生的C2单元（如硫胺素激活的乙醛）与磷酸丙糖衍生物的C-2羰基的缩合，该磷酸丙糖衍生物可能来自磷酸二羟丙酮而非丙酮酸，以及（ii）源于一个转位步骤。尽管这种假设的生物合成途径类似于L-缬氨酸的生物合成途径，但这种氨基酸或其C5前体可以被排除在异戊烯单元形成的中间体之外。
