Formation of protoporphyrin from coproporphyrinogen in extracts of various bacteria

The enzyme system capable of converting coproporphyrinogen to protoporphyrin was demonstrated in the soluble fraction of extracts of Pseudomonas fluorescens grown aerobically, of P. denitrificans grown anaerobically under denitrifying conditions, and of Escherichia coli grown both aerobically and anaerobically. Protoporphyrin accumulation by each of these extracts occurred only if the assay was conducted aerobically. Attempts to replace this oxygen requirement with several alternate electron acceptors were not successful. The conversion of coproporphyrinogen to protoporphyrin could not be demonstrated in extracts of the heme-containing organisms Staphylococcus epidermidis and Bacillus subtilis.