Glyceraldehyde-3-phosphate dehydrogenase

This enzyme serves two functions in this step. First the enzyme transfers a hydrogen (H-) from glyceraldehyde phosphate to the oxidizing agent nicotinamide adenine dinucleotide (NAD+) to form NADH. Next it adds a phosphate (P) from the cytosol to the oxidized glyceraldehyde phosphate to form 1, 3-bisphosphoglycerate.

Chemical equation

$NAD + G3P + Pi \rightleftharpoons 1,3BPG + NADH$

Rate equation

$v = \frac{ V_{mf}\frac{[NAD][G3P][Pi]}{K_{NAD}K_{G3P}K_{Pi}} - V_{mr} \frac{[BPG][NADH]}{K_{BPG}K_{NADH}} }{1 + \frac{[NAD]}{K_{NAD}} + \frac{[NAD][G3P]}{K_{NAD}K_{G3P}} + \frac{[NAD][G3P][Pi]}{K_{NAD}K_{G3P}K_{Pi}} + \frac{[BPG][NADH]}{K_{BPG}K_{NADH}} + +\frac{[NADH]}{K_{NADH}} }$