Fig. 1. (A) Single enzyme molecules are encapsulated in nanogels by surface acryloylation of a protein molecule followed by aqueous in situ polymerization. (B) Based on the analysis of enzyme sequences and the characteristic chemical patterns on enzyme surfaces, four-monomer random heteropolymers to mimic intrinsically disordered proteins are designed for enzyme solubilization and stabilization in nonnative environments. Reproduced with permission [18]. Copyright 2018, American Association for the Advancement of Science. (C) Enzyme molecules are directly embedded in inorganic crystals by a coprecipitation method. (D) In situ generation of Pd nanoparticles/clusters in a confined environment of a single lipase-polymer conjugate.

Fig. 2. (A) Scanning electron microscopy (SEM) images of calcinated Cyt c@ZIF-8. (B) The relative peroxidase activities of Cyt c, Cyt c@ZIF-8 composite, PVP/Cyt c mixture, Cyt c/zinc ion mixture, Cyt c/2-methylimidazole mixture, and Cyt c/ZIF-8 mixture. Reproduced with permission [21]. Copyright 2014, American Chemical Society. (C) NU-1000 encapsulation changes the coordination of the Cyt c heme active site. Probability distributions, P(D), of the N (His 18), S (Met 80), and C (Pro 30) distances relative to Fe in bulk. (D) Corresponding probability distributions inside MOF NU-1000. (E) The configurations of Cyt c in water. (F) The configurations of Cyt c inside MOF NU-1000. Reproduced with permission [23]. Copyright 2020, American Chemical Society. (G) Schematic illustration of the enzymatic cascade catalyzed by GOx/HRP@ZIF-8. (H) The relative overall activity of the enzyme cascade catalyzed by GOx/HRP_dx@ZIF-8 (x = 23, 17, 15, 13, 11, 10) without CAT or (I) with CAT. (J) Reaction kinetics (number of products, np, versus simulation time) of different radii of enzyme clusters, r = 5, 6, 7, 8, 9, 10, 11(σ) without intermediate decay or (K) with intermediate decay. Reproduced with permission [46]. Copyright 2019, Royal Society of Chemistry.

Fig. 3. (A) Cryo-electron tomography (Cryo-ET) reconstruction and magnified image of a single GOx-aZIF composite. (B) Structure of aZIF by molecular simulations (insets: schemes showing coordination). (C) Density functional theory (DFT) pore size distribution of ZIF-8, amorphous ZIF, and GOx-incorporated amorphous ZIF. (D) X-ray total scattering data and synchrotron radiation X-ray pair distribution function (PDF) of aZIF and ZIF-8. (E) Enzymatic activities of enzyme-ZIF-8 and enzyme-incorporated amorphous ZIFs, including GOx, Candida antarctica lipase B (CALB) and catalase (CAT). Reproduced with permission [52]. Copyright 2019, Springer Nature. (F) Thermal stability of free native HRP and HRP-MOF composites at 60 and 70 °C, respectively. Reproduced with permission [53]. Copyright 2020, American Association for the Advancement of Science.

Fig. 4. (A) Structure of the CALB-Pluronic conjugate with a Pd cluster and principles of DKR of amines catalyzed by CALB and Pd cluster. (B) Structure of the CALB-Pluronic conjugate in benzene. (C) Enzyme activities of Pd/CALB-P hybrid catalyst assayed by ester hydrolysis. (D) Fluorescence spectra of CALB, CALB-P conjugates and xPd/CALB-P hybrid catalysts (x = 0.8, 1.6, 2.2 and 2.5). (E) Free-energy profiles for (S)-1-PEA racemization on pristine Pd(111) and partially oxidized Pd(111) surfaces. (F) Catalytic performance of 0.8Pd/CALB-P at 55 °C and of a combination of commercially available Novozym 435 and Pd/C at 70 and 55 °C for the DKR reactions. (G) Conversions and ee values in ten cycles of the reaction using 0.8Pd/CALB-P as the catalyst. Reproduced with permission [56]. Copyright 2019, Springer Nature.