Boosted activity by engineering the enzyme microenvironment in cascade reaction: A molecular understanding.

Engineering of enzyme microenvironment can surprisingly boost the apparent activity. However, the underlying regulation mechanism is not well-studied at a molecular level so far. Here, we present a modulation of two model enzymes of cytochrome (Cty C) and -amino acid oxidase (DAAO) with opposite pH-activity profiles using ionic polymers. The operational pH of poly (acrylic acid) modified Cyt C and polyallylamine modified DAAO was extended to 3-7 and 2-10 where the enzyme activity was larger than that at their optimum pH of 4.5 and 8.5 by 106% and 28%, respectively. The cascade reaction catalyzed by two modified enzymes reveals a 1.37-fold enhancement in catalytic efficiency compared with their native counterparts. The enzyme activity boosting is understood by performing the UV-vis/CD spectroscopy and molecular dynamics simulations in the atomistic level. The increased activity is ascribed to the favorable microenvironment in support of preserving enzyme native structures nearby cofactor under external perturbations.