Question

1. CONGRADULATIONS! You have discovered a previously unknown metabolic pathway tha converts pyruvic acid to glyceraldehyde (structures are shown below). OH 0 H3C -COOH - HOC -C- CH pyruvic acid glyceraldehyde a. You have determined that this pathway uses a nicotinamide-containing enzyme coenzyme. Briefly explain if NADH is expected to exist as a product or reactant. b. Briefly explain if you expect ATP to be a product or reactant of this pathway.

Answer 1

a.In this metabolic pathway, NADH is expected to exist as a reactant .

The complete metabolic pathway can be viewed as a redox reaction in which a reduction event is coupled with an oxidation event. The conversion of pyruvic acid to glyceraldehyde is a reduction event which is coupled with the oxidation event of NADH to NAD+ .

b. In this reaction NADH is oxidised to NAD+ . This NAD+ is then recycled to NADH which is then used in ETC and substrate level phosphorylation to produce ATP. Thus in this pathway, ATP should be a product.