Out of 10 steps in glycolysis, only one reaction- Glyceraldehyde 3-phosphate (G3P) to 1,3-bisphosphoglycerate (PGP), uses NAD+ and thereby producing NADH. Furthermore, this very step is solely responsible for net gain of 2ATP in glycolysis since here phosphorylation occurs without the expenditure of ATP.
Why is NAD+ used only in this step? Is it possible to predict by other information that this is the only step to require NAD+? Is it possible to make this reaction happen without the involvement of NAD(P)+? Is it possible to skip this step and directly produce 3-phosphoglycerate (Lets not worry even if we cannot produce ATP in this process). I am interested in this because, this step necessitates the ferementation for regeneration of NAD+ in anaerobic condition. E. coli produced acetate as a side effect, as expected during anaerobic situations, but also rather unexpectedly during aerobic and high-growth rate situation (acetate-swtich, overflow problem). Production of acetate is unwanted in many industrial applications.