30783-27-8Relevant academic research and scientific papers
Revisiting the Mechanism of the Anaerobic Coproporphyrinogen III Oxidase HemN
Ji, Xinjian,Mo, Tianlu,Liu, Wan-Qiu,Ding, Wei,Deng, Zixin,Zhang, Qi
supporting information, p. 6235 - 6238 (2019/04/04)
HemN is a radical S-adenosyl-l-methionine (SAM) enzyme that catalyzes the oxidative decarboxylation of coproporphyrinogen III to produce protoporphyrinogen IX, an intermediate in heme biosynthesis. HemN binds two SAM molecules in the active site, but how these two SAMs are utilized for the sequential decarboxylation of the two propionate groups of coproporphyrinogen III remains largely elusive. Provided here is evidence showing that in HemN catalysis a SAM serves as a hydrogen relay which mediates a radical-based hydrogen transfer from the propionate to the 5′-deoxyadenosyl (dAdo) radical generated from another SAM in the active site. Also observed was an unexpected shunt product resulting from trapping of the SAM-based methylene radical by the vinyl moiety of the mono-decarboxylated intermediate, harderoporphyrinogen. These results suggest a major revision of the HemN mechanism and reveal a new paradigm of the radical-mediated hydrogen transfer in radical SAM enzymology.
The oxygen-independent coproporphyrinogen III oxidase HemN utilizes harderoporphyrinogen as a reaction intermediate during conversion of coproporphyrinogen III to protoporphyrinogen IX
Rand, Katrin,Noll, Claudia,Schiebel, Hans Martin,Kemken, Dorit,Duelcks, Thomas,Kalesse, Markus,Heinz, Dirk W.,Layer, Gunhild
, p. 55 - 63 (2011/11/05)
During heme biosynthesis the oxygen-independent coproporphyrinogen III oxidase HemN catalyzes the oxidative decarboxylation of the two propionate side chains on rings A and B of coproporphyrinogen III to the corresponding vinyl groups to yield protoporphyrinogen IX. Here, the sequence of the two decarboxylation steps during HemN catalysis was investigated. A reaction intermediate of HemN activity was isolated by HPLC analysis and identified as monovinyltripropionic acid porphyrin by mass spectrometry. This monovinylic reaction intermediate exhibited identical chromatographic behavior during HPLC analysis as harderoporphyrin (3-vinyl-8,13,17-tripropionic acid-2,7,12,18- tetramethylporphyrin). Furthermore, HemN was able to utilize chemically synthesized harderoporphyrinogen as substrate and converted it to protoporphyrinogen IX. These results suggest that during HemN catalysis the propionate side chain of ring A of coproporphyrinogen III is decarboxylated prior to that of ring B. by Walter de Gruyter.
Normal and abnormal heme biosynthesis. 6. Synthesis and metabolism of a series of monovinylporphyrinogens related to harderoporphyrinogen. further insights into the oxidative decarboxylation of porphyrinogen substrates by coproporphyrinogen oxidase
Lash, Timothy D.,Mani, Ukti N.,Keck, Anna-Sigrid I. M.,Jones, Marjorie A.
body text, p. 3183 - 3192 (2010/08/13)
A series of vinylporphyrinogens were prepared to probe the enzyme coproporphyrinogen oxidase (CPO). Six (2-chloroethyl)porphyrins were synthesized from a common dipyrrylmethane via a,c-biladiene intermediates in excellent yields. Subsequent dehydrohalogen
