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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 c (Cty C) and d-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.

An enzyme formulation using customized enzyme activators (metal ions) to directly construct metal–organic frameworks (MOFs) as enzyme protective carriers is presented. These MOF carriers can also serve as the disintegrating agents to simultaneously release enzymes and their activators during biocatalysis with boosted activities. This highly efficient enzyme preparation combines enzyme immobilization (enhanced stability, easy operation) and homogeneous biocatalysis (fast diffusion, high activity). The MOF serves as an ion pump that continuously provides metal ion activators that greatly promote the enzymatic activities (up to 251 %). This MOF–enzyme composite demonstrated an excellent protective effect against various perturbation environments. A mechanistic investigation revealed that the spontaneous activator/enzyme release and ion pumping enable enzymes to sufficiently interact with their activators owing to the proximity effects, leading to a boost in biocatalytic performance. [ABSTRACT FROM AUTHOR]

Abstract: Despite artificial nanozymes, as compared to natural enzymes, exhibit distinct superiorities of low cost, robustness against harsh environments, high stability and easy mass‐production, the relatively lower activity and efficiency still seriously restrict their application in high‐performance photometric chemosensing and biosensing. Promoting the activity and efficiency of nanozymes turns to be a significant yet challenging goal of the nanozyme community. Here we found, for the first time, that trace I− can dramatically boost the peroxidase‐like activity (over 50‐fold higher) of VOx at ppb‐concentration levels. It was deduced that the significant enhancement of nanozymatic activity mainly results from the synergetic modulation of surface redox and electronic structure of VOx. Based on this finding, ultrasensitive photometric detection of both H2O2 and I− (down to nM) was realized. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface phosphorus (P) doped Co 3 O 4 for PMS activation was first reported. • Such P doping could well preserve the textual characteristics of parent particles. • P doped Co 3 O 4 exhibited significant increase in oxygen vacancy and hydrophilicity. • P dopants endowed Co sites with boosted catalytic ability toward PMS activation. • SO 4 − - and 1O 2 -involved mechanism was unveiled. Recently, Co 3 O 4 has been widely utilized as heterogeneous catalyst for peroxymonosulfate (PMS) activation to eliminate various organic pollutants. However, for practical applications, the catalytic efficiency of pure Co 3 O 4 , limited by its simple monometal oxide component, needs further improvement. In a departure from the conventional doping method employing metal elements as dopants, herein, it is demonstrated that non-metal element doping offers a new and promising avenue to optimize the property of Co 3 O 4 and thus improve its catalytic performance. This was exemplified by phosphorus (P)-doped Co 3 O 4 (P-Co 3 O 4), which was obtained by a simple low-temperature annealing of commercial Co 3 O 4 using NaH 2 PO 2 as the P source. Noticeably, owing to the presence of P dopants (0.15 wt%), the cobalt sites in P-Co 3 O 4 exhibited higher affinity, easier electron transfer, and stronger bond-weakening ability for PMS relative to those in non-doped Co 3 O 4 , which led to a boosted catalytic activity. The degradation of rhodamine B (RhB) by P-Co 3 O 4 /PMS was verified to be SO 4 − - and 1O 2 -dominated and underwent a multistep mineralization pathway, and its kinetic rate constant (0.139 min−1) was 4.5 times that (0.031 min−1) of RhB degradation by Co 3 O 4 /PMS. Moreover, the P-Co 3 O 4 exhibited excellent reusability, without obvious catalytic activity loss after six successive runs. Our work presents an unconventional strategy for designing cost-effective and efficient heterogeneous cobalt-based catalysts for PMS activation. [ABSTRACT FROM AUTHOR]

Apart from the O releasing at a low rate, large polarization at a high rate is also a big challenge for Li-rich Mn-based oxide (LMO). Prussian blue (PB) with a specific redox potential is regarded as a suitable coating layer to overcome these drawbacks, while its stability is easily destroyed by the intrinsic Jahn-Teller effect after a long run. Herein, Mn vacancy (M V ) is introduced into the PB coating layer to enhance its stability. Consequently, such an electrode (M V -PB@LMO) presents a prolonged lifespan compared to the electrode with a PB coating layer only. Furthermore, it is found that the electrode with Mn vacancy in LMO (M V @LMO) shows superior reversibility, which displays a boosted activity of LMO. This research exhibits the advanced merits of Mn vacancy for LMO, and further work may pay more attention to strengthening of the stability of M V @LMO.

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 c (Cty C) and d -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., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors.)