Biosynthesis of porphyrins and related macrocycles. Part 15. Chemical and enzymic formation of uroporphyrinogen isomers from unrearranged aminomethylpyrromethane: separation of isomeric coproporphyrin esters

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Abstract
The unrearranged pyrromethane (1) is transformed chemically mainly into uro'gen-I with a smaller amount of uro'gen-IV but only traces of uro'gen-III are formed. Uro'gen-I is produced via a tetrapyrrolic (bilane) intermediate and when the deaminase–cosynthetase enzyme system from Euglena gracilis is present, this intermediate is converted into uro'gen-III. The rearrangement step for this conversion has the same characteristics found earlier for the natural biosynthetic process from porphobilinogen. Pyrromethane (1) is not a direct biosynthetic precursor of uro'gen-III and reasons are advanced why this is understandable. Methods are developed based on high pressure liquid chromatography for the separation of all four isomeric coproporphyrin esters.