Tetrapyrrole biosynthesis from 4,5-dioxovaleric acid in rhodopseudomonas spheroides.

Prophyrin biosynthesis from 4,5-dioxovaleric acid was studied in cell suspensions of R. spheroides. The experiments show that 4,5-dioxovaleric acid is a far precursor of porphyrins through delta amino laevulinic acid formation in a transmination reaction involving also l-alanine. It differs radically from the classical delta aminolaevulinic acid synthesis using glycine and succinyl CoA as substrates.