Biocatalyzed gold nanoparticle synthesis for the in situ detection of horseradish peroxidase inhibitor (phenylhydrazine) has been demonstrated.

Amitava Mukherjee

Centre for Nanobiotechnology

Vellore Campus

Chandra Sekaran N

Parashar A

Sachin Kedare P

Alex S.A

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

New Journal of Chemistry

Schematic representation for spectrophotometric detection of Hg2+ using an enzyme-mediated formation of silver nanoparticles.

Horseradish peroxidase-mediated in situ synthesis of silver nanoparticles: application for sensing of mercury

Background Peroxidations mediated by heme-enzymes have been traditionally studied under a single-site (heme distal pocket), non-sequential (ping-pong), two-substrates binding scheme of Michaelis-Menten paradigm. We had reported unusual modulations of peroxidase and P450 reaction outcomes and explained it invoking diffusible reactive species [Manoj, 2006; Manoj et al., 2010; Andrew et al., 2011, Parashar et al., 2014 & Venkatachalam et al., 2016]. Methods A systematic investigation of specific product formation rates was undertaken to probe the hypothesis that involvement of diffusible reactive species could explain undefined substrate specificities and maverick modulations (sponsored by additives) of heme-enzymes. Results When the rate of specific product formation was studied as a function of reactants' concentration or environmental conditions, we noted marked deviations from normal profiles. We report that heme-enzyme mediated peroxidations of various substrates are inhibited (or activated) by sub-equivalent concentrations of diverse redox-active additives and this is owing to multiple redox equilibriums in the milieu. At low enzyme and peroxide concentrations, the enzyme is seen to recycle via a one-electron (oxidase) cycle, which does not require the substrate to access the heme centre. Schemes are provided that explain the complex mechanistic cycle, kinetics & stoichiometry. Conclusion It is not obligatory for an inhibitor or substrate to interact with the heme centre for influencing overall catalysis. Roles of diffusible reactive species explain catalytic outcomes at low enzyme and reactant concentrations. Significance The current work highlights the scope/importance of redox enzyme reactions that could occur "out of the active site" in biological or in situ systems. © 2016 Elsevier B.V. and Société française de biochimie et biologie Moléculaire (SFBBM). All rights reserved.

Biochimie

Atypical profiles and modulations of heme-enzymes catalyzed outcomes by low amounts of diverse additives suggest diffusible radicals' obligatory involvement in such redox reactions

A novel and highly sensitive probe for the detection of organophosphorus compounds (OPs) using acetylcholinesterase (AChE) and acetylthiocholine (ATCh) during the modulated synthesis of silver nanoparticles.

RSC Advances

Developing acetylcholinesterase-based inhibition assay by modulated synthesis of silver nanoparticles: applications for sensing of organophosphorus pesticides

Applied Surface Science

A high-performance hydrazine electrochemical sensor based on gold nanoparticles/single-walled carbon nanohorns composite film

Journal of Materials Chemistry A

Enhanced electrocatalytic activity of gold nanoparticles on hydroxyapatite nanorods for sensitive hydrazine sensors

Chem. Commun.

Sodium borohydride stabilizes very active gold nanoparticle catalysts

A novel enzyme-mediated gold nanoparticle synthesis and its application for in situ detection of horseradish peroxidase inhibitor phenylhydrazine

Journal	Data powered by TypesetNew Journal of Chemistry
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	1144-0546
Open Access	0