The rate of lysostaphin-catalyzed lysis of staphylococci follows the Michaelis-Menten equation at [E](0) << [S](0), i.e., the activity of the enzyme is proportional to its concentration. This equation is proposed for determining the specific activity of lysostaphin. The apparent activation energy of hydrolysis of pentaglycine bridges in Staphylococcus peptidoglycan is 77.9 kJ/mol.
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http://dx.doi.org/10.1023/b:biry.0000040199.64244.b4 | DOI Listing |
Methods Mol Biol
January 2025
Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
This study describes an intramolecular quenching assay to evaluate gamma-secretase (GS) enzyme activity in human dermal cells. The method utilizes a fluorogenic peptide substrate, mimicking a fragment of amyloid precursor protein (APP), in which a quencher suppresses the fluorescence of a fluorophore until enzymatic cleavage occurs, resulting in a measurable increase in fluorescence. This real-time, direct measurement of GS activity allows for precise kinetic analysis using Michaelis-Menten modeling to define Kd and Vmax.
View Article and Find Full Text PDFMolecules
December 2024
Department of Pharmaceutical Science, College of Pharmacy and Health Sciences, Texas Southern University, 3100 Cleburne Street, Houston, TX 77004, USA.
Background: The aim of this study is to determine the impact of species and tissue differences on the glucuronidation of diclofenac in vitro.
Method: Microsomes from different species (rat, monkey, mouse, dog, and human) and rat and human tissues (liver, intestine, and kidney) were used to assess the rate of glucuronidation reaction of diclofenac. The metabolites were quantified using ultra high-performance liquid chromatography (UHPLC) and fitted into a Michaelis-Menten model to determine the metabolic kinetic parameters.
Entropy (Basel)
November 2024
Catalysis and Transient Kinetics Group, Idaho National Laboratory, Idaho Falls, ID 83415, USA.
The ubiquitous two-step Michaelis-Menten and Temkin-Boudart reaction mechanisms are extended to include the influence of the catalyst electronic subsystem in a 5-step mechanism. The resulting kinetic equation provides an alternative explanation for the well-known volcano-shaped dependence found in catalysis. The equilibrium constants of fast electronic steps are highlighted for their influence on adsorption and desorption through the relative concentration of charged versus neutral intermediates.
View Article and Find Full Text PDFEnzyme Microb Technol
December 2024
Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, College of Chemistry and Materials, Nanning Normal University, Nanning 530001, PR China.
The immobilization of α-amylase and glucoamylase using a metal-organic framework (enzyme@ZIF-8) was prepared in situ through a one-pot method. The morphology, crystal structure, and molecular characteristics of the free enzyme and enzyme@ZIF-8 were characterized. The enzyme@ZIF-8 exhibited the rhombic dodecahedron morphology, with a decrease in particle size.
View Article and Find Full Text PDFPLoS Comput Biol
January 2025
Genesupport, Avenue de Sévelin 18, Lausanne, Switzerland.
Catalysis and specifically autocatalysis are the quintessential building blocks of life. Yet, although autocatalytic networks are necessary, they are not sufficient for the emergence of life-like properties, such as replication and adaptation. The ultimate and potentially fatal threat faced by molecular replicators is parasitism; if the polymerase error rate exceeds a critical threshold, even the fittest molecular species will disappear.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!