Enzyme Hyperactivation System Based on a Complementary Charged Pair of Polyelectrolytes and Substrates

Abstract

Artificial enzyme activators are of great interest for enzyme applications in a wide range of research fields. Here, we report an enzyme hyperactivation system using polyelectrolytes that are complementary to charged substrates. The enzyme activity of α-chymotrypsin (ChT) for a cationic substrate increased 7-fold at pH 7.0 in the presence of anionic poly(acrylic acid) (PAAc) and for an anionic substrate increased 18-fold at pH 7.0 in the presence of cationic poly(allylamine) (PAA). Analysis of salt and pH effects, enzyme kinetics, dynamic light scattering (DLS), and circular dichroism (CD) indicated that the enzyme activation results from favorable electrostatic interactions between oppositely charged substrates and polyelectrolytes surrounding the enzymes. This hyperactivation system does not require laborious mutagenesis or chemical modification of enzymes and thus is relevant to a number of applications.

Enhanced Activity of Immobilized or Chemically Modified Enzymes

“…Moreover, the 1/K m was linearly increased with the corona thickness of PIC micelles, indicating that the corona layer of PIC micelles can accumulate substrates, serving as a substrate 'reservoir'. 43a A more detailed mechanism was demonstrated by the hyperactivation of α-chymotrypsin (ChT) in polymeric complexes(Figure 3) 44. The enzymatic activity of ChT towards cationic substrates was enhanced by 7-fold in the presence of anionic ploy (acrylic acid) (PAAc), while its activity towards anionic substrates by 18-fold in the presence of cationic poly (allylamine) (PAA).…”

Substrate Sorting by a Supercharged Nanoreactor

“…This proteasome mimic has a number of advantages over previously described synthetic polymers that also exploit electrostatic interactions to modulate protease activity. 26,27 First, it is completely modular and forms spontaneously under a wide range of conditions, including at physiological ionic strength, simply by mixing the components either in vitro or in vivo. 13,18 Second, as a genetically programmable material, its properties can be precisely tailored by standard molecular biological approaches.…”

Wrap-and-Strip Technology of Protein–Polyelectrolyte Complex for Biomedical Application

“…In contrast, protein activity can be increased rather substantially by a specific combination of substrate and polyelectrolyte (Figure 1d showing that enzyme activity decreased with increasing concentration of NaCl; hyperactivation was not observed at a concentration of 300 mM NaCl [64]. This is because electrostatic interactions among the enzyme, polyelectrolyte, and substrate play an important role in hyperactivation.…”