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Unusual Levels of Oxygen Consumption by Coproporphyrinogen Oxidase
Author(s) -
Morgenthaler Justin Bradley,
Bhagat Chirag,
Lash Timothy,
Jones Marjorie
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a45
Subject(s) - oxygen , substrate (aquarium) , chemistry , enzyme , heme , biochemistry , biology , organic chemistry , ecology
The enzyme Coproporphyrinogen Oxidase (CO) is the sixth enzyme in the biosynthetic pathway for heme. This particular enzyme carries out two sequential oxidative decarboxylations using the substrate Coproporphyrinogen‐III to yield a divinyl product. For aerobic organisms, molecular oxygen is required for this enzyme to be catalytically active. However the stoichiometry of oxygen usage relative to divinyl product is not well established. Using the Orion® Oxygen Electrode made by Thermo Electron Corporation, the oxygen consumed during catalysis was measured. Several different substrate analogs were also tested to estimate stoichiometry. Surprisingly, it was found that the poorer the substrate the more oxygen was consumed. This suggests that the mechanism for this enzyme is more complex than previously postulated.