Manipulation of enzyme activity at will presents various research and industrial applications. Herein we describe development of a technology for inactivation and reactivation of enzyme activities using a polyanionic poly(acrylic acid) (PAAc) and a polycationic poly(allylamine) (PAA). Enzyme activities of ribonuclease A (RNase A), lysozyme, cellulase, and α-amylase were lost through addition of PAAc or PAA because of their binding to the enzymes. The activity of these enzymes except for α-amylase was then fully restored from the complex by the addition of oppositely charged polymers. Such manipulation of enzyme activity using a complementary polymer pair system (CPPS) enables the expansion of biomedical and biotechnological applications of the enzymes, including realization of protein delivery and intelligent bioreactors
