Alright, we’ve finally made it to the enery making phase. In a lot of chemistry and science, the naming scheme just sort of flows in a way that makes you think they know how hard it is to study some of this stuff. We’re going to take our glyceraldehyde 3-P and apply…glyceraldehyde 3-P dehydrogenase. When in doubt on a test, just look for an answer like this. It’s going to take 1 phosphate and 1 NAD+, per glyceraldehyde 3-phophate. So, just assume we’ve got two of them going through this process which makes it 2 phosphates and 2 NAD+’s. Slap those phosphates onto the first carbons (1 for each, don’t lose track) and pop off the hydrogens that we’re sitting there.

Not quite that straight forward, but close. Those phosphate groups are actually going to bring their own oxygens with them which will do the attaching to the 1st carbon. The hydrogens that came off will attach to the NAD+’s making them NADH’s, which will go on to make more energy (electronic transport chain!). Now, 3 carbons in a row, double bond to oxygen on the first carbon and attached to phosphates on the first and third carbon, we’ll call it 1,3-bisphosphoglycerate.

Step 6, using phosphoglycerate kinase, rip that phosphate off the first carbon. Right, the ones that we just put on. Those go onto ADPs we spent earlier, making them ATPs. Okay, probably not exactly those ADPs but for illustrative purposes. We’re left over with 3-phosphoglycerate.

That gets mutated by phosphogylcerate mutase, moving the phosphate from the third carbon to the second carbon, making it 2-phosphoglycerate.

2-phosphoglycerate gets dehydrated by enolase (pops off 2 hydrogens and an oxygen, making H2O). That leaves us with phosphoenolpyruvate (make sure to track the names of the substrates and how they relate to the enzymes!)

Our phosphoenolpyruvate (PEP) has that last phosphate sitting on the second carbon. That gets popped off by pyruvate kinase and is given to an ADP to turn it into ATP (double it since we should be working with 2 PEPs, right?) and that leaves us with (2x) pyruvate. Again, this is irreversible and basically the last step. From here, pyruvate can be used for other processes, but it can also be converted into lactate by…lactate dehydrogenase. This is usually in the absence of oxygen. Lactate can be broken down into lactic acid which is the burning sensation you get when doing too many sets at the gym.

Whew – that’s a quite a bit of information. We’ll follow up with future articles on other energy pathways as well as how to regulate them all!