ID   1.14.99.57
DE   heme oxygenase (mycobilin-producing).
CA   (1) heme b + 3 AH2 + 3 O2 + 2 H(+) = mycobilin a + Fe(2+) + 3 A + 3 H2O.
CA   (2) heme b + 3 AH2 + 3 O2 + 2 H(+) = mycobilin b + Fe(2+) + 3 A + 3 H2O.
CC   -!- The enzyme, characterized from the bacterium Mycobacterium
CC       tuberculosis, is involved in heme degradation and iron utilization.
CC   -!- The enzyme binds two stacked protoheme molecules per monomer.
CC   -!- Unlike the canonical heme oxygenases, the enzyme does not release
CC       carbon monoxide or formaldehyde; instead, it forms unique products,
CC       named mycobilins, that retain the alpha-meso-carbon at the ring
CC       cleavage site as an aldehyde group.
CC   -!- EC 1.6.2.4 can act as electron donor in vitro.
DR   P9WKH2, MHUD_MYCTO ;  P9WKH3, MHUD_MYCTU ;
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