531-14-6Relevant articles and documents
Spectral and kinetic investigation on oxidation and reduction of water soluble porphyrin-manganese(III) complex
Giovannetti, Rita,Alibabaei, Leila,Pucciarelli, Filippo
, p. 1561 - 1567 (2010)
In this work the oxidation and reduction reactions of MnIII-Coproporphyrin-I (MnIII-CPI) have been studied and four forms of manganese-CPI complexes have been characterized. This complex was observed to be highly reactive (at basic pH) towards Mn(II), hypochlorite, hydrogen peroxide and oxone, forming [MnIV(O)CPI(OH)]- that was unstable and, after a short time, formed again [MnIIICPI(OH)2]-. With an excess of NaClO, a further oxidation of the complex [MnIV(O)CPI(OH)]-, provoked a significant spectral change for the [MnV(O)CPI(OH)] formation that showed, in the time, a partial polymerization. [MnIIICPI(OH)2]- was reduced by sodium dithionite to form the very unstable complex of [MnIICPI(OH)]- that successively degraded with Mn(II) release.
Abiotic formation of uroporphyrinogen and coproporphyrinogen from acyclic reactants
Lindsey, Jonathan S.,Chandrashaker, Vanampally,Taniguchi, Masahiko,Ptaszek, Marcin
supporting information; scheme or table, p. 65 - 75 (2011/04/14)
Tetrapyrrole macrocycles (e.g., porphyrins) have long been proposed as key ingredients in the emergence of life, yet plausible routes for forming their essential pyrrole precursor have previously not been identified. Here, the anaerobic reaction of δ-aminolevulinic acid (ALA, 5-240 mM) with 5-methoxy-3-(methoxyacetyl)levulinic acid (1-AcOH, 5-240 mM) in water (pH 5-7) at 25-85°C for a few hours to a few days affords uroporphyrinogen, which upon chemical oxidation gives uroporphyrin in overall yield of up to 10%. The key intermediate is the α-methoxymethyl-substituted analogue of the pyrrole porphobilinogen (PBG). Reaction of ALA and the decarboxy analogue of 1-AcOH (1-Me) gave coproporphyrinogen (without its biosynthetic precursor uroporphyrinogen as an intermediate); oxidation gave the corresponding coproporphyrin in yields comparable to those for uroporphyrin. In each case a mixture of porphyrin isomers was obtained, consistent with reversible oligopyrromethane formation. The route investigated here differs from the universal extant biosynthetic pathway to tetrapyrrole macrocycles, where uroporphyrinogen (isomer III) - nature's last common precursor to corrins, heme, and chlorophylls - is derived from eight molecules of ALA (via four molecules of PBG). The demonstration of the spontaneous self-organization of eight acyclic molecules to form the porphyrinogen under simple conditions may open the door to the development of a chemical model for the prebiogenesis of tetrapyrrole macrocycles. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.
Studies on the formation of porphyrinogens from monopyrroles in presence of the enzymes PBG deaminase and/or Uro'gen III synthase
Pichon-Santander, Clotilde,Ian Scott
, p. 8669 - 8672 (2007/10/03)
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.
