In biochemistry, allosteric regulation is the regulation of an enzyme or other protein by bining an effector molecule at the protein's allosteric site (that is, a site other than the protein's active site). Effectors that enhance the protein's activity are referred to as allosteric activators, whereas those that decrease the protein's activity are called allosteric inhibitors. The term allostery comes from the Greek allos, "other," and stereos, "space," referring to the regulatory site of an allosteric protein's being separate from its active site. Allosteric regulations are natural example of control loops, such as feedback from downstream products or feedforward from upstream substrates.