Uptake and Utilization of DL-[2-¹⁴C] Mevalonic Acid by Hevea brasiliensis

Abstract

THE high efficiency of incorporation of DL-3-hydroxy-3-methyl-[2-¹⁴C] pentano-5-lactone (DL-[2-¹⁴C] mevalonic acid) into cholesterol in rat-liver homogenates was first shown by Tavormina, Gibbs and Huff¹, who concluded that the lactone could provide an active 5-carbon isoprenoid unit which was used in direct biosynthesis. It was further found that this unit was derived from the lactone by elimination of C₁ as carbon dioxide². These results have been confirmed and extended to squalene biosynthesis^3–5, the pattern of isotopic labelling determined by degradation agreeing with that required for the synthesis of squalene from intact 5-carbon units³. Further proof of a general utility of the lactone in isoprenoid biosynthesis is shown by its incorporation into β-carotene in Phycomyces blakesleeanus and carrot slices⁶, and in Mucor hiemalis ⁷. The present communication describes briefly the further extension of this field to the uptake and utilization of DL-[2-¹⁴C] mevalonic acid by a rubber-producing plant, Hevea brasiliensis.