The Enzymatic Conversion of Porphobilinogen to Uroporphyrinogen Catalyzed by Extracts of Hematopoietic Mouse Spleen

Abstract

Abstract Uroporphyrinogen I synthetase has been isolated and partially purified from homogenates of spleens from phenylhydrazine-treated mice. One mole of uroporphyrinogen is formed for each 4 moles of porphobilinogen consumed. In the presence of uroporphyrinogen III cosynthetase from wheat germ, the product formed by the synthetase is uroporphyrinogen III. A second fraction from the mouse spleen, which lacks synthetase activity, can replace the wheat germ enzyme in the formation of uroporphyrinogen III by spleen or spinach synthetase. This indicates the presence of uroporphyrinogen III cosynthetase in a mammalian tissue.