In this study, the behavior of enzyme activity as a function of pH and temperature is modeled on the basis of fundamental considerations. A formulation is developed that includes the activation of enzymes with increasing temperatures and the deactivation of enzymes at higher temperature, together with the effect of protonation and hydroxylation on activity at various constant pH levels. The model is calibrated and validated against an extensive set of experimental data on phytases from seven different origins. The percentage variance accounted for (R(2)(adj)), obtained by statistical nonlinear regression analysis on all data sets, was shown to range from 97.6% to 99.5%. The equilibrium constant of protonation and hydroxylation proved to be independent of temperature.
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http://dx.doi.org/10.1002/1097-0290(20010205)72:3<323::aid-bit9>3.0.co;2-i | DOI Listing |
ChemistryOpen
January 2025
Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
5-Enolpyruvylshikimate-3-phosphate synthase (EPSPS) catalyzes the conversion of 5-enolpyruvate (PEP) and shikimic acid phosphate (S3P) to 5-enolpyruvylshikimic acid-3-phosphate (EPSP), releasing inorganic phosphate. This reaction is the sixth step of the shikimate pathway, which is a metabolic pathway used by microorganisms and plants for the biosynthesis of aromatic amino acids and folates but not in mammals. In the present study, the detailed reaction mechanism of EPSPS from Nicotiana tabacum (NtEPSPS) is revealed by quantum chemical calculations with the cluster approach.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, China.
Light-driven direct conversion of methane to formic acid is a promising approach to convert methane to value-added chemicals and promote sustainability. However, this process remains challenging due to the complex requirements for multiple protons and electrons. Herein, we report the design of WO-based photocatalysts modified with Pt active sites to address this challenge.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Krakow city, Poland.
Fly ash, produced during coal combustion for energy making, which is recognized as an industrial by-product, could lead to environmental health hazards. Subsequently, fly ash found that an exceptional adsorption performance for the removal of various toxic pollutants, the adsorption capacity of fly ash might be altered by introducing physical/chemical stimulation. Successfully converting fly ash into zeolites not only recovers their disposal difficulties but also transforms unwanted materials into merchandisable products for various industrial applications.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
University of Michigan - Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China.
Proton conducting electrochemical cells (PCECs) are efficient and clean intermediate-temperature energy conversion devices. The proton concentration across the PCECs is often nonuniform, and characterizing the distribution of proton concentration can help to locate the position of rate-limiting reactions. However, the determination of the local proton concentration under operating conditions remains challenging.
View Article and Find Full Text PDFBiosens Bioelectron
March 2025
School of Chemistry and Chemical Engineering, Institute of Environmental Science, Shanxi University, Taiyuan, 030006, PR China. Electronic address:
The fluctuation of ion content has an important effect on human health and ecological environment. Herein, a novel colorimetric and fluorescent dual mode probe (DMHB) has been designed via the imine bond bridging of anthraquinone derivative dye and salicyl hydrazide. The DMHB displays significance wide-range pH dependent spectral behavior (pKa 5.
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