Hi Corey Bender -

Great question. Indeed an enzyme itself may have an allosteric site on the same subunit as the active site but its location is different to the active site. Most cases they are small pockets that change the structural state of the subunit/s or allow for post translational signalling for a chemical modification to the enzyme for modulation. So in essence your allosteric site can be anywhere on the enzyme (different subunit as active site OR the same subunit as active site) - just not in the active site ofcourse ;) The complexity also increases as you go from a monomer to dimer and higher in solution...which then goes into binding orders. If this is something that you would like to know more about I would recommend a book like "Enzymes:..." by Robert Copeland. There are a few neat diagrams and schemes that explain this question pictorially.

Yes, I think theoretically this makes sense, but I haven't yet found an example of this in nature. I do plan to check Copeland, as well. Thanks!

Yeah there are not many of them published. I know of a few published structures of monomeric enzymes that have small molecules bound in allosteric sites-some on the same domain as the active site and others that are within a different domain of the monomer. I can link the papers in the comments if you are interested

Sure, Blake, any references you can provide would be great! So far, I haven't found a definitive (verifiable) mention in Copeland. The text does seem to indicate this is true, but doesn't give an example or reference to follow up, so if you have at least one, that would be fabulous. Much appreciated!