Bienzyme–Polymer–Graphene Oxide Quaternary Hybrid Biocatalysts: Efficient Substrate Channeling under Chemically and Thermally Denaturing Conditions

Abstract

An example of a highly stable and functional bienzyme–polymer conjugate triad assembled on a topologically orthogonal support, layered graphene oxide (GO), is reported here. Glucose oxidase (GOx) and horseradish peroxidase (HRP) catalytic dyad were used as the model system for cascade biocatalysis. Poly(acrylic acid) (PAA) was used to covalently conjugate these enzymes, and then the conjugate has been subsequently adsorbed onto GO. The resultant nanobiocatalysts are represented as GOx-HRP-PAA/GO. Their morphology and structural characteristics were examined by transmission electron microscopy (TEM), agarose gel electrophoresis, circular dichroism (CD), and zeta potential. These robust conjugates remarkably functioned as active catalysts under biologically challenging conditions such as extreme pHs, high temperature (65 °C), and in the presence of a chemical denaturant. In one example, GOx-HRP-PAA/GO presented doubling of the Kcat (TON) (68 × 10–2 s–1) at pH 7.0 and room temperature, when compared to the c...