The effects of succinylacetone (4,6-dioxoheptanoic acid) on delta-aminolevulinate synthase activity and the content of heme in monolayers of chick embryo liver cells.

Succinylacetone was shown to inhibit aminolevulinate dehydratase (5-aminolevulinate hydro-lyase (adding 5-aminolevulinate and cyclizing), EC 4.2.1.24) to reduce cellular heme and porphyrins and to induce delta-aminolevulinate synthase (succinyl-CoA:glycine C-succinyltransferase (decarboxylating), EC 2.3.1.37) in monolayers of chick embryo liver cells. Marked synergistic effects on delta-aminolevulinate synthase activity were obtained by combining succinylacetone with levulinate and porphyrogenic drugs. The time course of delta-aminolevulinate synthase activity showed a delayed synergistic response.