Biosynthetic and environmental effects on the stable carbon isotopic compositions of anteiso- (3-methyl) and iso- (2-methyl) alkanes in tobacco leaves

Nicotiana tabacum is the only plant known to biosynthesise large quantities of anteiso-alkanes and iso-alkanes (in the C29-C33 carbon number range). We investigated the carbon isotope ratios of the latter compounds extracted from tobacco. The anteiso-alkanes are enriched in 13C by 2‰ compared to the n-alkanes and iso-alkanes, supporting a different biosynthetic precursor (2-methylbutanoyl C5-CoA).