Acetyl-CoA

Catalysis

Thiamine pyrophosphate

Bacteria

Biology

Pyruvate dehydrogenase complex

Zymomonas mobilis

Dihydroxyacetone phosphate

Source rock

Cofactor

Pyruvate decarboxylation

Metabolism

Biochemistry

Phosphate

Thiamine

Stereochemistry

Paleontology

Genetics

Structural basin

Biosynthesis

Enzyme

Propionibacterium

Chemistry

Hopanoids

Ethanol fuel

Fermentation

Decarboxylation

Biochemical Journal

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.

Isoprenoid biosynthesis in bacteria: a novel pathway for the early steps leading to isopentenyl diphosphate