Studies on the formation of porphyrinogens from monopyrroles in presence of the enzymes PBG deaminase and/or Uro’gen III synthase

The substrate-specificities of two enzymes in the biosynthetic pathway to vitamin B₁₂, PBG deaminase and Uro’gen III synthase, which are involved in the formation of Uro’gen III from the pyrrole PBG, are investigated for the preparation of Uroporphyrin analogs. Both enzymes display strong substrate-specificity. However, tetramerization of pyrroles with carboxylate β-substituents in mildly basic buffer represents the best and most rapid route to a family of Uro I analogs for enzymatic activity studies.