When reading about ACh receptors, it is frequently the case that a protein is described as (alpha) or (non-alpha). However, I haven't really been able to find out what that means. What is the difference, and why would it matter if a subunit is alpha or not?


1 Answer 1


Achetylcholine (ACh) receptor is a pentamer of two alpha chains, and one each of the beta, delta, and gamma (in immature muscle) or epsilon (in mature muscle) chains.

  • $\begingroup$ I see. So is it called alpha simply because there are always two when the others are only one? $\endgroup$ Commented Dec 13, 2017 at 11:35
  • $\begingroup$ an alpha subunit is alpha; a non-alpha subunit is beta, gamma, delta, or epsilon. $\endgroup$
    – user37894
    Commented Dec 14, 2017 at 8:26
  • $\begingroup$ I fear that still doesn't clarify. The subunits are different proteins, is that right? That being the case, is there anything special about alpha? I assume so, since the sub units are grouped as "alpha" and "non-alpha", implying that alpha has special status, doesn't it? $\endgroup$ Commented Dec 14, 2017 at 14:26
  • 2
    $\begingroup$ The alpha subunit contains the acetylcholine binding site. Lyddiatt et al. (1979) FEBS Lett 108: 20-24 (ncbi.nlm.nih.gov/pubmed/520545); Sumikawa et al. (1982) Nucl Acids Res 10: 5809-5822 (ncbi.nlm.nih.gov/pubmed/6183641). $\endgroup$
    – user37894
    Commented Dec 15, 2017 at 7:50

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