Studies on ferrochelatase. 2. An in vestigation of the role offerrochelatase in the biosynthesis of various haem prosthetic groups

Abstract

The preparation, and some of the properties, of pig-liver ferrochelatase, an enzyme system converting porphyrin and Fe2+ ions into haem, have been described by Porra and Jones (1963). Though it is reasonable to assume that ferrochelatase is involved in the enzymic sequence leading to the formation of the haem moiety of haemoproteins other than haemoglobin, there is no direct evidence to support this hypothesis. The adult mammalian liver, which synthesizes haemoglobin only in certain pathological conditions, is rich in cytochromes, and the ferrochelatase activity detected in this tissue may be involved in the biosynthesis of cytochrome prosthetic groups. To obtain more conclusive evidence for the participation of ferrochelatase in the biosynthesis of haemoproteins other than haemoglobin, the occurence of this enzyme was sought in micro-organisms. We have also tested the substrate specificity of a ferrochelatase preparation from pig liver with a number of porphyrins related to haem prosthetic groups.