Question

Why are two equivalents of NADPH required to reduce hydroxymethylglutanyl-CoA to mevalonic acid?

Short answer

NADPH undergoes oxidation and reduction of redox reaction. And Nicotinamide Adenine Dinucleotide Phosphate comes in two forms: oxidized (NADP+) and reduced (NADPH).

For reducing hydroxymethylglutanyl-CoA into mevalonic acid, two equivalents of NADPH are needed.

Step-by-step solution

Difference between NADH and NADPH.

In NADPH, there is a presence of a phosphate group that distinguishes two separate equivalents of co-enzymes, in order to maintain the different ratios between NADH and NADPH.

However, both NADH and NADPH undergo oxidation and reduction reactions.

Why is NADPH required?

NADPH is required to reduce hydroxymethylglutanyl-CoA to mevalonic acid. NADH is generally found in glycolysis and Kreb’s cycle but NADPH is involved in photosynthesis.

Why two equivalents of NADPH is required?

NADP⁺ is the oxidized form of NADPH. Many anabolic events, including the production of all main cell components and many biotechnological products, are fueled by the reducing power of two equivalent of NADPH.