Label-Free LC/HRMS-Based Enzymatic Activity Assay for the Detection of DDC, MAO and COMT Inhibitors in Natural Extracts

2021 ◽  
Author(s):  
Abha Harfouche ◽  
Wael Alata ◽  
Karine Leblanc ◽  
Bruno Figadère ◽  
Alexandre Maciuk
Keyword(s):  
Enzymatic Activity ◽  
Label Free ◽  
Activity Assay ◽  
Comt Inhibitors ◽  
Natural Extracts ◽  
Enzymatic Activity Assay

scholarly journals Identification of Small Molecule Inhibitors of the Deubiquitinating Activity of the SARS-CoV-2 Papain-Like Protease: in silico Molecular Docking Studies and in vitro Enzymatic Activity Assay

2020 ◽  
Vol 8 ◽  
Author(s):  
Eleni Pitsillou ◽  
Julia Liang ◽  
Katherine Ververis ◽  
Kah Wai Lim ◽  
Andrew Hung ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Enzymatic Activity ◽  
Small Molecules ◽  
Binding Site ◽  
Protein Docking ◽  
Activity Assay ◽  
Epicatechin Gallate ◽  
Inhibitor Binding ◽  
Enzymatic Activity Assay

COVID-19 is an ongoing pandemic caused by the SARS-CoV-2 virus with important political, socio-economic, and public health consequences. Inhibiting replication represents an important antiviral approach, and in this context two viral proteases, the SARS-CoV-2 main and papain-like proteases (PLpro), which cleave pp1a and pp1ab polypeptides, are critical. Along with protease activity, the PLpro possesses deubiquitinating activity, which is important in immune regulation. Naphthalene-based inhibitors, such as the well-investigated GRL-0617 compound, have been shown to possess dual effects, inhibiting both protease and deubiquitinating activity of the PLpro. Rather than binding to the canonical catalytic triad, these type of non-covalent inhibitors target an adjacent pocket, the naphthalene-inhibitor binding site. Using a high-throughput screen, we have previously identified the dietary hypericin, rutin, and cyanidin-3-O-glucoside compounds as potential protease inhibitors targeting the naphthalene-inhibitor binding site. Here, our aim was to investigate the binding characteristics of these compounds to the PLpro, and to evaluate deubiquitinating activity, by analyzing seven different PLpro crystal structures. Molecular docking highlighted the relatively high affinity of GRL-0617 and dietary compounds. In contrast binding of the small molecules was abolished in the presence of ubiquitin in the palm subdomain of the PLpro. Further, docking the small molecules in the naphthalene-inhibitor binding site, followed by protein-protein docking revealed displacement of ubiquitin in a conformation inconsistent with functional activity. Finally, the deubiquitinating activity was validated in vitro using an enzymatic activity assay. The findings indicated that the dietary compounds inhibited deubiquitinase activity in the micromolar range with an order of activity of GRL-0167, hypericin >> rutin, cyanidin-3-O-glucoside > epigallocatechin gallate, epicatechin gallate, and cefotaxime. Our findings are in accordance with mechanisms and potential antiviral effects of the naphthalene-based, GRL-0617 inhibitor, which is currently progressing in preclinical trials. Further, our findings indicate that in particular hypericin, rutin, and cyanidin-3-O-glucoside, represent suitable candidates for subsequent evaluation as PLpro inhibitors.

scholarly journals A Label-Free LC/MS/MS-Based Enzymatic Activity Assay for the Detection of Genuine Caspase Inhibitors and SAR Development

2013 ◽  
Vol 18 (8) ◽  
pp. 868-878 ◽  
Author(s):  
Michel C. Maillard ◽  
Celia Dominguez ◽  
Mark J. Gemkow ◽  
Florian Krieger ◽  
Hyunsun Park ◽  
...  
Keyword(s):  
Published Data ◽  
Tandem Mass ◽  
Label Free ◽  
Activity Assay ◽  
Fluorogenic Substrates ◽  
Enzymatic Assays ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Enzymatic Activity Assay ◽  
Assay Interference

The resurgence of interest in caspases (Csp) as therapeutic targets for the treatment of neurodegenerative diseases prompted us to examine the suitability of published nonpeptidic Csp-3 and Csp-6 inhibitors for our medicinal chemistry programs. To support this effort, fluorescence-based Csp-2, Csp-3, and Csp-6 enzymatic assays were optimized for robustness against apparent enzyme inhibition caused by redox-cycling or aggregating compounds. The data obtained under these improved conditions challenge the validity of previously published data on Csp-3 and Csp-6 inhibitors for all but one series, namely, the isatins. Furthermore, in this series, it was observed that the nature of the rhodamine-labeled substrate, typically used to measure caspase activity, interfered with the pharmacological sensitivity of the Csp-2 assay. As a result, a liquid chromatography/tandem mass spectrometry–based assay that eliminates label-dependent assay interference was developed for Csp-2 and Csp-3. In these label-free assays, the activity values of the Csp-2 and Csp-3 reference inhibitors were in agreement with those obtained with the fluorogenic substrates. However, isatin 10a was 50-fold less potent in the label-free Csp-2 assay compared with the rhodamine-based fluorescence format, thus proving the need for an orthogonal readout to validate inhibitors in this class of targets highly susceptible to artifactual inhibition.

Enzymatic activity assay of d-hydantoinase by isothermal titration calorimetry. Determination of the thermodynamic activation parameters for the hydrolysis of several substrates

2006 ◽  
Vol 67 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Montserrat Andújar-Sánchez ◽  
Francisco Javier Las Heras-Vázquez ◽  
Josefa María Clemente-Jiménez ◽  
Sergio Martínez-Rodríguez ◽  
Ana Camara-Artigas ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Isothermal Titration Calorimetry ◽  
Activation Parameters ◽  
Titration Calorimetry ◽  
Activity Assay ◽  
Thermodynamic Activation Parameters ◽  
Hydrolysis Of ◽  
Enzymatic Activity Assay

scholarly journals Antibacterial Activity of Caffeic Acid Combined with Ultraviolet-A Light against Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes

2021 ◽  
Author(s):  
Min-Young Park ◽  
Dong-Hyun Kang
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Listeria Monocytogenes ◽  
Enzymatic Activity ◽  
Caffeic Acid ◽  
Membrane Damage ◽  
Ultraviolet A ◽  
Activity Assay ◽  
Natural Polyphenol ◽  
Enzymatic Activity Assay

The aim of this study was to evaluate the antibacterial activity of caffeic acid (CA) which is a natural polyphenol, combined with Ultraviolet-A (UV-A) light against the representative foodborne bacteria, Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes. The inactivation results were obtained depending on the CA concentration, light wavelength and light dose.E. coli O157:H7 and S. Typhimurium were reduced to the detection limit when treated with 3 mM CA and UV-A for 3 J/cm2 and 4 J/cm2 respectively, and 5 J/cm2 treatment induced 3.10 log reduction in L. monocytogenes. To investigate the inactivation mechanism, measurement of polyphenol uptake, membrane damage assessment, enzymatic activity assay, and transmission electron microscopy (TEM) were conducted against S. Typhimurium and L. monocytogenes. It was revealed that CA was significantly (P < 0.05) absorbed by bacterial cells, and UV-A light allowed a higher uptake of CA for both pathogens. Additionally, CA + UV-A treatment induced significant (P < 0.05) cell membrane damage. In the enzymatic activity assay, both pathogens showed a reduction in their activity by CA and a higher reduction occurred by CA + UV-A. Moreover, TEM images indicated that CA + UV-A treatment notably destroyed the intercellular structure. In addition, antibacterial activity was also observed in commercial apple juice, which showed similar results to those obtained from PBS, resulting in a significant (P < 0.05) reduction for all three pathogens without any changes in color parameters (L*, a*, and b*), total phenolic compounds and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity. IMPORTANCE Photodynamic inactivation (PDI), which involves photoactivation of a photosensitizer (PS), is an emerging field of study as it effectively reduces various kinds of microorganisms. Although there are several PSs that have been used for PDI, there is a need to find naturally occurring PSs for safer application in food industry. Caffeic acid, a natural polyphenol found in most of fruits and vegetables, has recently been studied for its potential to act as a novel photosensitizer. However, no studies have been conducted regarding its antibacterial activity depending on treatment conditions and its antibacterial mechanism. In this study we closely examined the effectiveness of caffeic acid in combination with UV-A light for inactivating representative foodborne bacteria in liquid medium. Therefore, the results of this research are expected to be utilized as basic data for future application of caffeic acid in PDI, especially when controlling pathogens in liquid food processing.

Colorimetric Enzymatic Activity Assay Based on Noncrosslinking Aggregation of Gold Nanoparticles Induced by Adsorption of Substrate Peptides

2008 ◽  
Vol 9 (9) ◽  
pp. 2301-2308 ◽  
Author(s):  
Jun Oishi ◽  
Yoji Asami ◽  
Takeshi Mori ◽  
Jeong-Hun Kang ◽  
Takuro Niidome ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Enzymatic Activity ◽  
Activity Assay ◽  
Enzymatic Activity Assay

scholarly journals A Rapid Two-Step Iduronate-2-Sulfatatse Enzymatic Activity Assay for MPSII Pharmacokinetic Assessment

2017 ◽  
pp. 89-95 ◽  
Author(s):  
Mitra Azadeh ◽  
Luying Pan ◽  
Yongchang Qiu ◽  
Ruben Boado
Keyword(s):  
Enzymatic Activity ◽  
Activity Assay ◽  
Pharmacokinetic Assessment ◽  
Enzymatic Activity Assay

scholarly journals In vitro enzymatic activity assay for ENOLASE in mammalian cells in culture

2012 ◽  
Author(s):  
Florian Muller ◽  
Florian Muller ◽  
Elisa Aquilanti ◽  
Ronald DePinho
Keyword(s):  
Enzymatic Activity ◽  
Mammalian Cells ◽  
Activity Assay ◽  
Cells In Culture ◽  
Enzymatic Activity Assay

A radiochemical enzymatic activity assay for glycerol kinase and hexokinase

1967 ◽  
Vol 132 (2) ◽  
pp. 338-346 ◽  
Author(s):  
E.A. Newsholme ◽  
J. Robinson ◽  
K. Taylor
Keyword(s):  
Enzymatic Activity ◽  
Glycerol Kinase ◽  
Activity Assay ◽  
Enzymatic Activity Assay

scholarly journals A scalable lysyl hydroxylase 2 expression system and luciferase-based enzymatic activity assay

2017 ◽  
Vol 618 ◽  
pp. 45-51 ◽  
Author(s):  
Hou-Fu Guo ◽  
Eun Jeong Cho ◽  
Ashwini K. Devkota ◽  
Yulong Chen ◽  
William Russell ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Expression System ◽  
Activity Assay ◽  
Lysyl Hydroxylase ◽  
Enzymatic Activity Assay
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