Decoding MOF-Enzyme-Substrate Compatibility for Universal Biocatalyst Immobilization.

Abstract

Metal-organic frameworks (MOFs) are widely used for enzyme immobilization due to their tunable pore structures and high stability. However, whether a relatively universal MOF carrier can support diverse enzymatic reactions remains unclear. Herein, we systematically evaluated 120 MOF-enzyme-substrate combinations using ten representative MOFs, three hydrolases (CRL, CALB, and BsEst), and four ester substrates, and then extended the identified carriers to three additional enzymes spanning catalase, oxidase, and protease reactions (GOx, Typ, and BlCAT), examining each with a single substrate. Overall, UiO-66 and UiO-66-NH2 showed the most consistently favorable relative apparent activity. Among the selected materials, UiO-66 and UiO-66-NH2 emerged as universal carriers, enhancing catalytic activity by up to 1.6-fold compared with free enzymes under harsh conditions, including elevated temperatures, pH 3.5-10.5, and the presence of toxic molecules. Molecular dynamics simulations combined with the analysis of 45 structural, solvation, and energetic descriptors revealed two key mechanisms underlying the superior performance of Enzyme/UiO-66(-NH2) systems: preservation of internal hydrogen-bond networks in both substrate-bound and substrate-free states, and framework-assisted substrate enrichment near active sites through enhanced adsorption. This work provides molecular insights into MOF-enzyme-substrate interactions and establishes potentially transferable design principles for the MOF-mediated immobilization of other enzymes.