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The final step of heme biosynthesis is the insertion of iron into protoporphyrin IX (OMIM 612386). This reaction is catalyzed by the mitochondrial enzyme ferrochelatase (see Fig. 1). Ferrochelatase utilizes protoporphyrin IX, rather than its reduced form, as substrate, but requires the reduced ferrous form of iron .
Jul 19, 2022 · Primarily, the four acetate groups are decarboxylated into methyls by uroporphyrinogen decarboxylase (UROD, E.C. 4.1.1.37), turning uroporphyrinogen III into coproporphyrinogen III. Secondly, coproporphyrinogen III oxidase (CPO, E.C. 1.3.3.3) that localizes to the intermembrane space converts two out of four propionate residues into vinyls.
May 1, 2023 · The correct porphyrin ring III forms, and then the side chains of uroporphyrinogen III are modified, catalyzed by uroporphyrinogen decarboxylase to produce coproporphyrinogen III. Following its synthesis, coproporphyrinogen III gets transported into mitochondria.
Fig. 1 Diagram of heme biosynthetic pathway, showing that a defect in any step causes excess accumulation of porphyrin or porphyrin precursors. * = Hydroxymethylbilane can spontaneously convert into uroporphyrin I and subsequently into coproporphyrin I. ALA = ∂-aminolevulinic acid; CoA = coenzyme A; PBG = porphobilinogen. View Large Image.
May 24, 2010 · Depending on the organism, ALA is either synthesized by condensation of glycine with succinyl-CoA or from tRNA-bound glutamate via glutamate-1-semialdehyde. B: Uroporphyrinogen III is converted into heme in four consecutive enzymatic steps via the intermediates coproporphyrinogen III, protoporphyrinogen IX, and protoporphyrin IX.
Aug 8, 2006 · Heme (iron protoporphyrin IX) is an essential molecule for numerous living organisms. Not only does it serve as a prosthetic group in enzymes, it also acts as a signaling molecule that controls...
May 3, 2019 · PPOX1 is targeted exclusively to plastids, providing Proto for heme and chlorophyll synthesis 3, while PPOX2 was found in plastid envelope and mitochondria in spinach 4. However, N. tabacum PPOX2...
