Biosynthetic incorporation of [β-14C; 3,5-2H2; 4-3H]cinnamic acid into capsaicin and norpluviine: lack of an apparent isotope effect following an NIH shift

Abstract

Biosynthetic experiments with [4-³H]-, [4-³H; 3,5-²H₂]- and [3-³H]cinnamic acid, using Capsicum annuum and “Texas” daffodils, have shown that hydroxylation at C-4 involves migration of hydrogen to the neighbouring carbon (the “NIH shift”) and that the aromatisation step following migration involves no apparent isotope effect and is presumably stereospecific and enzymically controlled.