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Formation of phenols from aromatic subtrates by plant and animal mono-oxygenases: The effect of adjacent deuteriums on the magnitude of the NIH shift of tritium

1973; Elsevier BV; Volume: 154; Issue: 2 Linguagem: Inglês

10.1016/0003-9861(73)90019-2

1096-0384

Donald J. Reed, J. Vimmerstedt, D. M. JERINA, John W. Daly,

Plant and fungal interactions

Hepatic metabolism of 4-[3H]acetanilide in vivo and in vitro yields 4-hydroxyacetanilide which retains, respectively, 40 and 62% of the tritium. When the 4-tritio-substrate contains adjacent deuteriums the retention of tritium is reduced to 26 and 40%. Hepatic metabolism of 4-[3H]anisole in vivo and in vitro yields 4-hydroxyanisole with 78% of the tritium. This retention is reduced to 62% in the corresponding 3,5-[2H2]-4[3H]anisole. Similarly, the retention of tritium in trans-4-hydroxycinnamic acid derived by metabolism of trans-[4-3H]cinnamic acid with chick pea microsomes is reduced from 91% to 68% by the presence of adjacent deuteriums in the substrate. Hydroxylation at the 4-position does not result in selective loss of tritium from the 3-position of acetanilide, anisole, or cinnamic acid. The above isotope effects indicate that isomerization of the probable arene oxide intermediates proceeds mainly via the keto-tautomer of the phenolic product.