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I'm wondering exactly how ligands bind to and release from receptors. Until recently I presumed ligands were attracted to receptors through electrostatic forces with no chemical interaction involved, and that catabolic enzymes (MAO, AChE) were simply present in the extracellular fluid. I hadn't given much thought as to how they disengage, but assumed ligands were brushed off by the extracellular fluid.

However, recently, I was reading about acetylcholinergic signaling and how it can be disrupted by, and I've come to realize is that everything I thought I knew about neurotransmission may be wrong. What I've read suggests this (article linked below):

  • AChE is membrane-bound

  • AChE is part of the AChR, or just happens to be is close enough proximity that the AChE can catabolize the ligand while bound to the receptor

  • The AChR attracts ACh's positively-charged amine, which brings the acetyl group within range of AChE's reactive alcohol group. This alcohol group cleaves the acetyl group from ACh

  • It is not until the acetyl group is cleaved that the ligand disengages from the receptor

My questions:

  • Is all of this correct?

  • Are the AChR and AChE distinct? If so, how can both simultaneously interact with a single molecule given their much larger size? If not, why are they ever spoken of as different?

  • Is this sort of catabolism-mediated disengagement the case with other neurotransmitters?

  • Where can I read more about this, and what is this sort of interaction called? It's been difficult finding information on this.

Here's the source I was reading on ACh transmission:

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closed as too broad by Christiaan, Robin Kramer, huh, Krysta, Steven Jeuris Jul 12 at 21:27

There are either too many possible answers, or good answers would be too long for this format. Please add details to narrow the answer set or to isolate an issue that can be answered in a few paragraphs.If this question can be reworded to fit the rules in the help center, please edit the question.

Look for the Coursera course "Drugs and the Brain" and see when it's offered next. It touches on a lot of these issues and more, and I think you would find it fascinating. Meanwhile, I'll see if I can answer some of this a bit later. – Chuck Sherrington Jul 31 '14 at 11:01
This is the text used in the course. It's gone up a lot in price, but it's very helpful. – Chuck Sherrington Jul 31 '14 at 11:03
I'm voting to close this question as off-topic because it's a biology question. – Christian Hummeluhr Apr 18 '15 at 13:41
@ChristianHummeluhr normally I would be inclined to agree with you, but Chuck's comment suggests that this could be a border-case between bio and our site. – Artem Kaznatcheev Apr 18 '15 at 17:31
@ArtemKaznatcheev That's what close votes are for, I suppose, but it doesn't seem to have anything to do with any behavioral variables at all, so I'm maintaining my vote. I might have been more inclined to agree if Chuck or another trusted user had attempted an answer rather than a quick comment. – Christian Hummeluhr Apr 19 '15 at 7:36

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