The Effect of Accessibility of Insoluble Substrate on the Overall Kinetics of Enzymatic Degradation.

The enzymatic reaction kinetics on cellulose and other solid substrates is limited by the access of the enzyme to the reactive substrate sites. We introduce a general model in which the reaction rate is determined by the active surface area, and the resulting kinetics consequently reflects the evolving relationship between the exposed substrate surface and the remaining substrate volume. Two factors influencing the overall surface-to-volume ratio are considered: the shape of the substrate particles, characterized by a single numerical parameter related to its dimensionality, and the distribution of the particle sizes.

Magnetically Responsive Enzyme and Hydrogen-Bonded Organic Framework Biocomposites for Biosensing.

The one-pot synthesis of multicomponent hydrogen-bonded organic framework (HOF) biocomposites is reported. The co-immoblization of enzymes and magnetic nanoparticles (MNPs) into the HOF crystals yielded biocatalysts (MNPs-enzyme@BioHOF-1) with dynamic localization properties. Using a permanent magnet, it is possible to separate the MNPs-enzyme@BioHOF-1 particles from a solution.

Keeping the Distance: Activity Control in Solid-Supported Sucrose Phosphorylase by a Rigid α-Helical Linker of Tunable Spacer Length.

Enzyme immobilization into carrier materials has broad importance in biotechnology, yet understanding the catalysis of enzymes bound to solid surfaces remains challenging. Here, we explore surface effects on the catalysis of sucrose phosphorylase through a fusion protein approach. We immobilize the enzyme via a structurally rigid α-helical linker [EAK] of tunable spacer length due to the variable number of pentapeptide repeats used ( = 6, 14, 19).

Expanding the high-pH range of the sucrose synthase reaction by enzyme immobilization.

The glycosylation of an alcohol group from a sugar nucleotide substrate involves proton release, so the reaction is favored thermodynamically at high pH. Here, we explored expansion of the alkaline pH range of sucrose synthase (SuSy; EC 2.4.

Electrochemically Induced Nanoscale Stirring Boosts Functional Immobilization of Flavocytochrome P450 BM3 on Nanoporous Gold Electrodes.

Enzyme-modified electrodes are core components of electrochemical biosensors for diagnostic and environmental analytics and have promising applications in bioelectrocatalysis. Despite huge research efforts spanning decades, design of enzyme electrodes for superior performance remains challenging. Nanoporous gold (npAu) represents advanced electrode material due to high surface-to-volume ratio, tunable porosity, and intrinsic redox activity, yet its coupling with enzyme catalysis is complex.