A substance, other than the
catalyst or one of the substrates, that increases the rate of a catalysed reaction without
itself being consumed; the process is called
activation. An activator of an enzyme-catalysed reaction may be called enzyme activator, if
it acts by binding to the enzyme.
Source:
PAC, 1993, 65, 2291
(Nomenclature of kinetic methods of analysis (IUPAC Recommendations 1993))
on page 2292