Poly(acrylic acid) is a Common Noncompetitive Inhibitor for Cationic Enzymes with High Affinity and Reversibility

We have recently developed a versatile technique, complementary polymer pair system (CPPS), which enables switching the activity of diverse enzymes using anionic poly (acrylic acid) (PAAc) and cationic poly(allylamine) (PAA). To obtain a deeper understanding of CPPS, we investigated the manner by which PAAc inhibits cationic ribonuclease A, lysozyme, and trypsin. Studies of the enzyme kinetics showed that PAAc acts as a noncompetitive inhibitor for all these enzymes, and carries several potent enzyme binding sites (K-i approximate to 10(-8) M). In addition, the inhibited enzymes were recovered by oppositely charged PAA. These data indicate the generality of CPPS, as only the surface charge and not the substrate binding site of the enzymes should be considered when determining a charged polymer as an inhibitor. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3835-3841,2011