Pyruvate dehydrogenase is a multi-enzyme complex. How many cofactors and coenzymes does it require?

1. An important step in the breakdown of glucose to yield energy is catalysis by a multi-enzyme complex called pyruvate dehydrogenase. 2. This complex of several enzymes requires one cofactor and five different organic coenzymes to catalyze its reaction. 3. The single cofactor is a magnesium ion, which fits the definition of a cofactor as an inorganic ion. 4. Reversing the counts to five cofactors and one coenzyme is the trap in the first option. 5. Because coenzymes come mainly from dietary vitamins, an enzyme needing five of them depends heavily on diet. 6. Enzyme function is therefore regulated in part by the abundance of cofactors and coenzymes supplied by the diet. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 6 "Metabolism", section 6.5 Enzymes_