This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cofactor and prosthetic groups, Subject name: Biochemistry
Carbon mono-oxide (CO) is released in reaction catalyzed by- 
Select and explain. 
A. Decarboxylases, B. Carboxylases, C. Heme oxygenase, D. Pyruvate Dehydrogenase
C: Heme oxygenase
Answer: C: Heme oxygenase 
Explanation: Heme Oxygenase (EC no- 1) catalyzes degradation of Heme by oxygenation and releasing CO in the reaction (see fig). With regard to other options which are as follows: Decarboxylases(Option a) - produce CO2 Elimination reactions. Carboxylases(Option b) - use CO2 as a Substrate. Pyruvate Dehydrogenase(Option d) - used to conve Pyruvate into Acetyl CoA formed in mitochondria.