This investigation concerns the effect of certain physical factors-viscosity, dielectric constant, ionic strength, and temperature of the medium-on the reaction of hydrogen peroxide and ferrocytochrome c in the presence of the enzyme horse-radish peroxidase. From study of the effects of viscosity and dielectric constant, it was concluded that the reaction between the secondary complex of hydrogen peroxide and enzyme on the one hand and ferrocytochrome c on the other is controlled by diffusion in media of high viscosity and by electrostatic effects at low viscosities. With respect to ionic strength, the data at pH 4.7 indicated a dipole-dipole interreaction. The temperature dependence of the over-all reaction had a Q(10) of 1.25.
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http://dx.doi.org/10.1016/s0006-3495(63)86833-2 | DOI Listing |
Biochem Cell Biol
January 2025
Department of Chemistry and Biomolecular Sciences, University of Ottawa, 150 Louis-Pasteur Pvt, Ottawa, ON K1N 6N5, Canada.
Ste2 and Ste3 are G-protein-coupled receptors (GPCRs) shown to play roles in hyphal chemotropism and fungal plant pathogenesis in response to activity arising from host-secreted peroxidases. Here, we follow up on the observation that chemotropism is dependent on both Ste2 and Ste3 being present; testing the possibility that this might be due to formation of an Ste2-Ste3 heterodimer. Bioluminescence resonance energy transfer (BRET) analyses were conducted in , where the addition of horse radish peroxidase (HRP) was found to increase the transfer of energy from the inducibly expressed Ste3-Nano luciferase donor, to the constitutively expressed Ste2-yellow fluorescent protein (YFP) acceptor, compared to controls.
View Article and Find Full Text PDFJ Immunol Methods
November 2024
Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain.
We present a time-course saturation ELISA for measuring the equilibrium constant of the monoclonal antibody (mAb) SIM 28 against horse radish peroxidase (HRP). The curves of HRP binding to a series of fixed mAb dilutions were plotted to completion, and the K (= K) value (time to occupy 50 % of the mAb paratopes) was determined for each mAb dilution and HRP concentration. Analysis of the kinetic mechanism of the reaction by Lineweaver-Burk and Hanes plots showed that the slope and y-intercept were affected, indicating that mAb ligand saturation follows non-competitive inhibition kinetics in this assay format.
View Article and Find Full Text PDFSTAR Protoc
September 2024
Department of Pediatric Hematology and Oncology, University Children's Hospital Muenster, Muenster, Germany; Princess Máxima Center for Pediatric Oncology, Utrecht, the Netherlands; Institute of Transfusion Medicine and Cell Therapy, University Hospital Muenster, Muenster, Germany; Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Muenster, Muenster, Germany. Electronic address:
The detection of disialoganglioside GD2 on tumor biopsies, especially in paraffin-embedded tissues, has been challenging due to the glycolipid structure of GD2 and its membrane anchorage. Here, we present an immunofluorescence protocol for the reliable assessment of GD2 on formalin-fixed paraffin-embedded (FFPE) tissues. We describe steps for antigen retrieval with Tris-EDTA buffer and staining with unconjugated anti-GD2 antibody (clone 14.
View Article and Find Full Text PDFTalanta
October 2024
Department of Chemistry, College of Science, Northeastern University, Shenyang, 110819, People's Republic of China. Electronic address:
Self-driven microfluidic systems have attracted significant attention and demonstrated great potential in the field of point-of-care (POC) testing due to their device simplicity, low power consumption, increased portability, and reduced sample consumption. To develop POC detection chips with diverse characteristics that meet different requirements, there is a strong demand for feasible strategies that enable easy operation and reduce processing time. Here, a one-step processing approach using femtosecond laser direct writing technology was proposed to fabricate a capillary-actuated POC microfluidic chip.
View Article and Find Full Text PDFTalanta
October 2024
Department of Chemistry, Capital Normal University, Beijing, 100048, China. Electronic address:
Although nanozyme engineering has made tremendous progress, there is a huge gap between them and natural enzymes due to the enormous challenge of precisely adjusting the geometric and electronic structure of active sites. Considering that intentionally adjusting the metal-carrier interactions may bring the promising catalytic activity, in this work, a novel Mo atom nanocluster is successfully synthesized using nitrogen-doped Mxene (Mo/N-MXene) nanozymes as carriers. The constructed Mo/N-MXene displays excellent peroxidase-like catalytic activity and kinetics, outweighing its N-MXene and Mo nanoparticles (NPs)-MXene references and natural horse radish peroxidase.
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