Accepted name: hydrogen peroxide-dependent heme synthase
Reaction: Fe-coproporphyrin III + 2 H2O2 = protoheme + 2 CO2 + 4 H2O (overall reaction)
(1a) Fe-coproporphyrin III + H2O2 = harderoheme III + CO2 + 2 H2O
(1b) harderoheme III + H2O2 = protoheme + CO2 + 2 H2O
Other name(s): coproheme III oxidative decarboxylase; hemQ (gene name)
Systematic name: Fe-coproporphyrin III:hydrogen peroxide oxidoreductase (decarboxylating)
Comments: The enzyme participates in a heme biosynthesis pathway found in Gram-positive bacteria. The initial decarboxylation step is fast and yields the three-propanoate harderoheme isomer III. The second decarboxylation is much slower. cf. EC, SAM-dependent heme synthase.
1.  Dailey, T.A., Boynton, T.O., Albetel, A.N., Gerdes, S., Johnson, M.K. and Dailey, H.A. Discovery and characterization of HemQ: an essential heme biosynthetic pathway component. J. Biol. Chem. 285 (2010) 25978–25986. [PMID: 20543190]
2.  Celis, A.I., Streit, B.R., Moraski, G.C., Kant, R., Lash, T.D., Lukat-Rodgers, G.S., Rodgers, K.R. and DuBois, J.L. Unusual peroxide-dependent, heme-transforming reaction catalyzed by HemQ. Biochemistry 54 (2015) 4022–4032. [PMID: 26083961]
3.  Hofbauer, S., Mlynek, G., Milazzo, L., Puhringer, D., Maresch, D., Schaffner, I., Furtmuller, P.G., Smulevich, G., Djinovic-Carugo, K. and Obinger, C. Hydrogen peroxide-mediated conversion of coproheme to heme b by HemQ-lessons from the first crystal structure and kinetic studies. FEBS J. 283 (2016) 4386–4401. [PMID: 27758026]
4.  Celis, A.I., Gauss, G.H., Streit, B.R., Shisler, K., Moraski, G.C., Rodgers, K.R., Lukat-Rodgers, G.S., Peters, J.W. and DuBois, J.L. Structure-based mechanism for oxidative decarboxylation reactions mediated by amino acids and heme propionates in coproheme decarboxylase (HemQ). J. Am. Chem. Soc. 139 (2017) 1900–1911. [PMID: 27936663]
[EC created 2019]