VCAC: Cellular Processes: Glycolysis - The Reactions: Advanced Look: Energy Production

The last five stages of glycolysis are known as the Energy Production Phase, because ATP is produced, along with NADH, during this half of the pathway. Clicking on each of the thumbnail images will bring up a larger, labeled version of the described scene.

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	The first five steps of glycolysis consume energy in the form of ATP. The second five steps produce energy in the form of ATP as well as NADH.
	Step six is catalyzed by a dehydrogenase enzyme, with glyceraldehyde 3-phosphate, NAD+, and inorganic phosphate (Pi) as the required substrates.
	Like all of the steps in the second half of glycolysis, step six occurs twice. The dehydrogenase facilitates the production of two molecules each of 1,3-bisphosphoglycerate, NADH and H+.
	Step seven involves another kinase enzyme and 1,3-bisphosphoglycerate and ADP as substrates.
	Step seven produces two molecules each of ATP and 3-phosphoglycerate, and is considered reversible, even though ATP is produced.
	Step eight is catalyzed by a mutase enzyme, and 3-phosphoglycerate is the required substrate.
	The mutase at step eight converts the two 3-phosphoglycerate molecules into two 2-phosphoglycerate molecules.
	Step nine involves another lyase enzyme and 2-phosphoglycerate as the required substrate.
	The lyase enzyme converts each 2-phosphoglycerate molecule into one molecule of phosphoenolpyruvate and one molecule of water, resulting in two water molecules and two molecules of phosphoenolpyruvate.
	The tenth and final step of glycolysis is catalyzed by another kinase enzyme, and requires ATP and phosphoenolpyruvate as substrates.
	The kinase converts the two molecules of phosphoenolpyruvate into two molecules each of pyruvate and ATP. This step is irreversible.
	At the end of glycolysis, one glucose molecule has been oxidized into two pyruvate molecules. Along the way, two molecules of NADH and four molecules of ATP were also produced, resulting in a net gain of two ATP and two NADH for the pathway.

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