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
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: http://www.umich.edu/~essen/html/web_mod/cobra/respiration_detailed.html