Comparative studies on nonenzymic and enzymic protoheme formation
1972; Elsevier BV; Volume: 264; Issue: 2 Linguagem: Inglês
10.1016/0304-4165(72)90290-5
ISSN1872-8006
Autores Tópico(s)Photosynthetic Processes and Mechanisms
ResumoNonenzymic and enzymic iron insertion into the protoporphyrin ring was studied. Nonenzymic protoheme formation from protoporphyrin IX and Fe2+ was demonstrated under strictly anaerobic conditions in the presence of (A) Na2S2O4 and (B) sodium lauryl sulfate. In System A, protoheme formation was observed with a yield of 30–50% over the pH range 7.8 to 9.6 using Tris-HCl buffer accompanied by the formation of black precipitate, presumably an iron-suflur complex. In system B, maximum protoheme formation at pH 8.2 was obtained with a yield of 46% in 0.1–0.3% sodium lauryl sulfate solution and increase with pH over the range 7.1–9.6. Nonenzymic heme formation from other porphyrins was also studied. Enzymic protoheme as well as other heme formations were studied with respect to reaction rates, effect of detergents and sulfhydryl inhibitors.
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