We have studied the peroxidase-oxidase reaction with NADH and O2 as substrates and melatonin as a cofactor in a semibatch reactor. We show for the first time that melatonin is an activator of the reaction catalyzed by enzymes from both plant and animal sources. Furthermore, melatonin promotes oscillatory dynamics in the pH range from 5 to 6. The frequency of the oscillations depends on the pH such that an increase in pH was accompanied by a decrease in frequency. Conversely, an increase in the flow rate of NADH or an increase in the average concentration of NADH resulted in an increase in oscillation frequency. Complex dynamics were not observed with melatonin as a cofactor. These results are discussed in relation to observations of oscillatory dynamics and the function of melatonin and peroxidase in activated neutrophils.
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http://dx.doi.org/10.1006/bbrc.2001.5047 | DOI Listing |
Chaos
December 2024
PhyLife, Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
A simple almost fifty year old four-variable model of the peroxidase-oxidase reaction has been studied using 2D isospike stability diagrams, 2D maximum Lyapunov exponent diagrams, and other nonlinear numerical methods. The model contains two positive feedback loops. For slightly different sets of parameters, compared to the original parameters, the model reveals a wealth of dynamic behaviors, not previously reported for this model.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
Single-atom nanozymes (SAzymes) with ultrahigh atom utilization efficiency have been extensively applied in reactive oxygen species (ROS)-mediated cancer therapy. However, the high energy barriers of reaction intermediates on single-atom sites and the overexpressed antioxidants in the tumor microenvironment restrict the amplification of tumor oxidative stress, resulting in unsatisfactory therapeutic efficacy. Herein, we report a multi-enzyme mimetic MoCu dual-atom nanozyme (MoCu DAzyme) with various catalytic active sites, which exhibits peroxidase, oxidase, glutathione (GSH) oxidase, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase mimicking activities.
View Article and Find Full Text PDFTalanta
August 2024
Department of Chemistry, College of Science, Sultan Qaboos University, Box 36, Al-Khod, 123, Oman.
This study presents a potent paper-based analytical device (PAD) for quantifying various sugars using an innovative bi-nanozyme made from a 2-dimensional Fe/Ce metal-organic framework (FeCe-BTC). The MOF showed excellent bifunctional peroxidase-oxidase activities, efficiently catalyzing luminol's chemiluminescence (CL) reaction. As a peroxidase-like nanozyme, FeCe-BTC could facilitate the dissociation of hydrogen peroxide (HO) into hydroxyl radicals, which then oxidize luminol.
View Article and Find Full Text PDFAnal Chem
March 2024
Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin 300050, China.
A multisignal method for the sensitive detection of norovirus based on Mn paramagnetic relaxation and nanocatalysis was developed. This dual-modality sensing platform was based on the strong relaxation generated by cracked Au@MnO nanoparticles (NPs) and their intrinsic enzyme-like activity. Ascorbic acid rapidly cracked the MnO layer of Au@MnO NPs to release Mn(II), resulting in the relaxation modality being in a "switch-on" state.
View Article and Find Full Text PDFNano Lett
February 2024
Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Sciences and Chemical Engineering, Harbin Engineering University, Harbin, 150001, P. R. China.
Ferroptosis is a novel type of nonapoptotic programmed cell death involving the accumulation of lipid peroxidation (LPO) to a lethal threshold. Herein, we propose tunable zeolitic imidazolate framework (ZIFs)-engineered biodegradable nanozymes for ferroptosis mediated by both reactive oxygen species (ROS) and nitrogen species (RNS). l-Arginine is utilized as an exogenous nitric oxide donor and loaded into hollow ZIFs@MnO artificial nanozymes, which are formed by etching ZIFs with potassium permanganate and simultaneously generating a MnO shell .
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