title: Hepta- and hexa-carboxylic porphyrinogen intermediates in haem biosynthesis.
abstract: In the course of our studies on intermediates in normal and abnormal metabolism of porphyrins we have synthesised a number of porphyrins related to uroporphyrin-III and compared them with materials isolated from natural sources. In the present paper we show that the corresponding porphyrinogens are all metabolised to protoporphyrin-IX by haemolysates of chicken erythrocytes, but at different rates. The results are discussed in relation to our conclusions concerning the preferred pathway of degradation of uro'gen-III to coproporphyrinogen-III, which indicate a clockwise sequence of decarboxylation reactions.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002645:Chickens; D003305:Coproporphyrinogens / Q000378:metabolism; D003653:Decarboxylation; D004912:Erythrocytes / Q000378:metabolism; D006418:Heme / Q000096:biosynthesis*; D006801:Humans; D011164:Porphyrias / Q000378:metabolism; D011165:Porphyrinogens / Q000378:metabolism*; D011524:Protoporphyrins / Q000378:metabolism
chemical_list: D003305:Coproporphyrinogens; D011165:Porphyrinogens; D011524:Protoporphyrins; D006418:Heme