Related Experiment Video
Updated: Sep 21, 2025

Author Spotlight: Innovating Thiol Quantification and Biomarker Detection for Oxidative Stress Research
Published on: June 28, 2024
Glutathione-dependent thioredoxin reduction and lipoamide system support in-vitro mammalian ribonucleotide reductase
Ajanta Chatterji1, Kumar Sachin2, Rajib Sengupta3,4
1Amity Institute of Biotechnology Kolkata, Amity University Kolkata, Action Area II, Kadampukur village, Rajarhat, Newtown, 700135, Kolkata, West Bengal, India.
Background:
The thioredoxin system (Trx), comprising of Trx, Thioredoxin reductase (TrxR) and NADPH aids in donating hydrogen group to support Ribonucleotide reductase (RNR) catalysis during de-novo DNA biosynthesis. However, it has been observed that inhibiting TrxR does not affect the viability of cancer cells that are susceptible to pharmacological glutathione (GSH) depletion. This prompted us to study the potential antioxidant redundancies that might prolong RNR activity.
Methods:
To study the RNR activity assay, the RNR complex was reconstituted by mixing purified mouse recombinant RNR subunits and the conversion of [3 H] CDP into [3 H] dCDP was monitored. In the assay system, either purified Trx and GSH or Lipoamide system was supplemented as reducing agents to support RNR catalysis.
Results:
Herein, we have found that GSH-dependent Trx reduction supports mammalian class I RNR catalysis in absence of TrxR in the system. Our data also presents the first report that the LAM system is capable of supporting in-vitro RNR activity in the complete absence of either Trx or Grx systems.
Conclusions:
We conclude that GSH-mediated Trx reduction and LAM systems support basal level RNR activity in vitro; in absence of TrxR and complete redoxin systems respectively and hypothesize that potential redundancy between the various antioxidant systems might synergize in sustaining RNR activity.
More Related Videos
07:16Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
08:57Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases
Published on: February 24, 2018
Related Concept Videos
Sulfur Assimilation
Redox Reactions
Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
Oxidation and Reduction of Organic Molecules
The removal of an electron from a molecule, results in a...