Final answer:
Allosteric control is the regulation of an enzyme through reversible binding of a modulator to a regulatory site on the enzyme, leading to conformational changes in the active site and affecting substrate binding and reaction rates.
Step-by-step explanation:
Regulation of an enzyme through reversible binding of a modulator to a regulatory site on an enzyme is specifically called allosteric control.
Allosteric enzymes have both a binding site, for substrate binding and catalysis, and an allosteric site, for regulation of enzyme activity. When a regulator molecule binds to the allosteric site of an enzyme, usually by noncovalent interactions, a conformational change occurs in the enzyme active site, which affects substrate binding and reaction rates. Allosteric regulation of enzyme activity can be either positive, increasing reaction rates, or negative, decreasing reaction rates.