A dual functional probe: sensitive fluorescence response to H2S and colorimetric detection for SO32−

Switchable catalysis offers opportunities to control the rate or selectivity of a reaction via a stimulus such as pH or light. However, few examples of switchable catalytic systems that can facilitate multiple processes exist. Here we report a rare example of such dual-functional, switchable catalysis. Featuring an easily prepared, bench-stable cobalt(I) hydride complex in conjunction with pinacolborane, we can completely alter the reaction outcome between two widely employed transformations – olefin migration and hydroboration – with visible light as the sole trigger. This dichotomy arises from ligand photodissociation which leads to metamorphosis of the active catalytic site, resulting in divergent mechanistic pathways.

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A Boronic Acid-Based Fluorescence Hydrogel for Monosaccharide Detection

10.26434/chemrxiv.7176989 ◽

2018 ◽

Author(s):

Suying Xu ◽

Adam Sedgwick ◽

Souad Elfecky ◽

Wenbo Chen ◽

Ashley Jones ◽

...

Keyword(s):

Fluorescent Probe ◽

Boronic Acid ◽

Binding Constants ◽

Strong Fluorescence ◽

Fluorescence Response ◽

Turn On ◽

Fluorescence Turn On ◽

Hydrogel System

A boronic acid-based anthracene fluorescent probe was functionalised with an acrylamide unit to incorporate into a hydrogel system for monosaccharide detection. In solution, the fluorescent probe displayed a strong fluorescence turn-on response upon exposure to fructose, and an expected trend in apparent binding constants, as judged by a fluorescence response where D-fructose > D-galactose > D-mannose > D-glucose. The hydrogel incorporating the boronic acid monomer demonstrated the ability to detect monosaccharides by fluorescence with the same overall trend as the monomer in solution with the addition of fructose resulting in a 10-fold enhancement (≤ 0.25 M).

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Directed Evolution of P450 Fatty Acid Decarboxylases via High-Throughput Screening Towards Improved Catalytic Activity

10.26434/chemrxiv.9791162 ◽

2019 ◽

Author(s):

Huifang Xu ◽

Weinan Liang ◽

Linlin Ning ◽

Yuanyuan Jiang ◽

Wenxia Yang ◽

...

Keyword(s):

Catalytic Activity ◽

Fatty Acid ◽

Directed Evolution ◽

High Throughput ◽

High Throughput Screening ◽

Colorimetric Detection ◽

Screening Method ◽

Random Mutagenesis ◽

Direct Production ◽

Consumption Activity

P450 fatty acid decarboxylases (FADCs) have recently been attracting considerable attention owing to their one-step direct production of industrially important 1-alkenes from biologically abundant feedstock free fatty acids under mild conditions. However, attempts to improve the catalytic activity of FADCs have met with little success. Protein engineering has been limited to selected residues and small mutant libraries due to lack of an effective high-throughput screening (HTS) method. Here, we devise a catalase-deficient Escherichia coli host strain and report an HTS approach based on colorimetric detection of H2O2-consumption activity of FADCs. Directed evolution enabled by this method has led to effective identification for the first time of improved FADC variants for medium-chain 1-alkene production from both DNA shuffling and random mutagenesis libraries. Advantageously, this screening method can be extended to other enzymes that stoichiometrically utilize H2O2 as co-substrate.

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Faculty Opinions recommendation of Colorimetric detection of DNA sequences based on electrostatic interactions with unmodified gold nanoparticles.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1021421.243581 ◽

2004 ◽

Author(s):

Vincent Rotello

Keyword(s):

Gold Nanoparticles ◽

Dna Sequences ◽

Electrostatic Interactions ◽

Colorimetric Detection

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