Multiple choice

Heme oxygenase

  1. can oxidize methene bridge between three pyrrole rings of heme

  2. requires molecular oxygen for its activity

  3. produces bilirubin and carbon dioxide

  4. can use protoporphyrin as substrate

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heme oxygenase is the enzyme that catalyzes the first step in heme degradation, which is the oxidation of the methene bridge between the pyrrole rings. This cleavage produces biliverdin, free iron, and carbon monoxide (not carbon dioxide). The enzyme does require molecular oxygen for its activity, but option A describes the core catalytic function more specifically.

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