-Aminolevulinic acid dehydratase of Rhodopseudomonas capsulata

δ-Aminolevulinic acid dehydratase, an enzyme which catalyzes the synthesis of the pyrrole, porphobilinogen, from two molecules of δ-aminolevulinic acid, has been purified 400-fold from Rhodopseudomonas capsulata. Some of its properties were compared to the enzyme from Rhodopseudomonas spheroides and to those from eucaryotic cells. The enzyme of R. capsulata appears to be both similar to that of R. spheroides in some respects and also similar to those of eucaryotic cells. The enzyme from R. capsulata does not require metallic cations for activation, is not inhibited by EDTA, and is insensitive to inhibition by hemin and protoporphyrin.