Determination of substrate binding affinity () is critical to understanding enzyme function. An extensive number of methods have been developed and employed to study ligand/substrate binding, but the best approach depends greatly on the substrate and the enzyme in question. Below we describe how to measure the of BesD, a non-heme iron halogenase, for its native substrate lysine using equilibrium dialysis with subsequent detection with High Performance Liquid Chromatography (HPLC). This method can be performed in anaerobic glove bag settings, requires readily available HPLC instrumentation for subsequent detection, and is adaptable to meet the needs of a variety of substrate affinity measurements.
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http://dx.doi.org/10.1101/2024.04.03.588023 | DOI Listing |
J Chromatogr B Analyt Technol Biomed Life Sci
December 2024
Department of Clinical Diagnostics, University Medical Centre Utrecht, Utrecht University, Utrecht, The Netherlands. Electronic address:
Introduction: High-dose systemic prednisolone is the cornerstone treatment of many autoimmune- and inflammatory diseases. Since prednisolone shows non-linear protein binding at higher serum concentrations, quantification of the unbound prednisolone concentration is important to understand prednisolone pharmacokinetics. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay to quantify protein-unbound prednisolone in serum.
View Article and Find Full Text PDFJ Pharm Sci
December 2024
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark. Electronic address:
Physiological and artificial solubilizing agents usually enhance apparent solubility of poorly soluble drugs, and in many cases also oral drug exposure. However, exposure may decrease in cases where micellization reduces the molecularly dissolved drug fraction, overriding the solubility advantage. While this information is critical to accurately anticipate the effect of drug micellization on oral absorption, the experimental determination of molecularly dissolved drug concentrations is complex and time consuming.
View Article and Find Full Text PDFEur J Drug Metab Pharmacokinet
December 2024
Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India.
Objective: The objective of this study was to determine the apparent intrinsic clearance (Cl) and fraction unbound in human liver microsomes (f) of 86 marketed central nervous system (CNS) drugs and to predict the in vivo hepatic blood clearance (CL).
Methods: Cl in human liver microsomes (HLM) was determined by substrate depletion, and f was determined by equilibrium dialysis. The relationship between lipophilicity (logP) and unbound intrinsic clearance (Cl) was explored using the Biopharmaceutical Drug Disposition Classification System (BDDCS) and Extended Clearance Classification System (ECCS).
J Am Chem Soc
December 2024
Polymer Reaction Design Group, School of Chemistry, Monash University, 19 Rainforest Walk, Building 23, Clayton, VIC 3800, Australia.
A continuous flow setup comprising an inline dialysis unit for immediate monomer removal is used for the depolymerization of poly(methyl methacrylate) (pMMA), synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The approach used allows one to carry out solution depolymerizations at much higher polymer content compared to batch processes while maintaining high depolymerization conversions. pMMA is efficiently depolymerized in the flow reactor, yielding up to 68% monomer recovery under catalyst-free reaction conditions at 160 °C, starting from a 1 molar repeat unit concentration, which is a 20-fold improvement compared to previous batch studies.
View Article and Find Full Text PDFSci Total Environ
December 2024
Lancaster University, Lancaster Environment Centre, Bailrigg, Lancaster LA1 4YQ, UK. Electronic address:
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