3
$\begingroup$

I am teaching myself Cell Biology from the internet. Despite my usually good Googling skills, I'm stuck in a loop with this question.

Q: What is the source of ATP?

A: ADP

Q: What is the source of ADP?

A: ATP

At first I thought that ATP synthase actually created ATP from scratch as intimated here:

ATP synthase is an important enzyme that creates the energy storage molecule adenosine triphosphate Wikipedia

I then realise that ATP synthase doesn't create ATP so much as convert ADP.

My Question

Can humans synthesise ADP/ATP from scratch. If so, where are these phosphates made and if not what food source provides them and how? Also, where do we get the phosphorus?

Thanks

$\endgroup$
6
$\begingroup$

Phosphorus is a very common nutrient, found in high levels in proteins, which are in such foods as milk and milk products, meat, beans, lentils, nuts, and grains, especially whole grains. Phosphorus is found in smaller amounts in vegetables and fruit, as well. Adenosine can be found in many of the same foods, both as free ATP/ADP/AMP, and as part of the DNA found in all animal and plant-based foods (are there any other kinds?).

Adenine (the nucleotide base before the addition of ribose creates adenosine) is synthesized via the purine synthesis pathway, whose ultimate product is IMP, or inosine monophosphate. IMP is then converted to adenylosuccinate, then to AMP, which is then phosphorylated to ATP. It should be noted that, as is the case in most biosynthetic pathways, this one requires ATP to power it along, meaning it takes ATP to make ATP.

$\endgroup$
  • $\begingroup$ Would the downvoter care to comment so I can improve my answer? What's wrong with it? $\endgroup$ – MattDMo Oct 25 '16 at 21:27
  • $\begingroup$ I can't imagine why this was downvoted (+1 from me). Maybe because a quick look at the wiki link obviously requires ADP/ATP in its own production and someone thought it was a circular answer? That's my best guess. $\endgroup$ – anongoodnurse Oct 26 '16 at 3:21
  • 2
    $\begingroup$ @anongoodnurse The question isn't "Where did the first molecule of ATP come from?", but I guess that's as good a guess as any. I just wish people would leave comments when there's nothing obviously wrong with an answer, like another answer directly contradicting it or something. Oh well, it's not like the rep is a big deal or anything. I just want to be loved! :) $\endgroup$ – MattDMo Oct 26 '16 at 11:46
  • $\begingroup$ Not my downvote but the only correction I would make is the phosphorous content of grains. They are very rich in phosphate but most of it is locked up in phytate which most mammals can't digest. If you go on a high grain vegetarian diet your phosphorous intake actually decreases. See: ncbi.nlm.nih.gov/pubmed/21183586 $\endgroup$ – mimat Nov 1 '16 at 11:16
  • $\begingroup$ @mimat Thanks for the feedback. Do you know how much is available from proteins and nucleic acids in whole grains as compared to the other foods I listed? That was kind of what I was getting at, not just the total phosphate levels regardless of bioavailability. Also, is phytate broken down by cooking, such that, for example, whole-grain bread has more bioavailable phosphorus than raw grains? $\endgroup$ – MattDMo Nov 1 '16 at 17:52

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.