Stereospecific regulation of in vivo prenyl chain elongation. Prenylation in higher plants.

This article involves the brief explanation on the stereochemical picture of Cornforth's basic principle for the isoprenoid biosynthesis and the integrated presentation of new findings on the unusual prenyl chain elongation, which does not follow Cornforth's basic principle, in higher plants.The new findings are as follows : (i) In the biosynthesis of polyprenols from mevalonic acid by the intact leaves of Mallotus japonicus, the formation of their Z -prenyl chain involved the unusual elimination of the pro-4S hydrogen of the mevalonic acid. (ii) When (E, E) -farnesol was synthesized from 3, 3-dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP) in the presence of iodoacetamide with the cell-free extract of Pisum sativum, the DMAPP was condensed with the carbon-carbon double bond of IPP from its reversed face, i. e., re-re face. Stereospecific models for explanation of these unusual phenomena are presented.