What exactly defines an allosteric enzyme? I've seen many definitions, such as "an enzyme that binds an effector at a site other than the active site," "an enzyme that changes conformation in response to binding an effector," and "an enzyme that has multiple active sites." From what I understand, all of these are true, but even enzymes that exhibit Michaelis-Menten kinetics bind effectors such as inhibitors at sites other than the active site (right?), and a change in conformation follows. Would this make these enzymes "allosteric?"