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Updated: Jul 3, 2026

Rapid Quantification of Oxidized and Reduced Forms of Glutathione Using Ortho -phthalaldehyde in Cultured Mammalian Cells In Vitro
Published on: June 28, 2024
Pro-oxidant shift in glutathione redox state during aging
Igor Rebrin1, Rajindar S Sohal
1Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, California 90089, USA.
Aging impairs cellular redox balance by increasing oxidative stress and reducing glutathione (GSH) biosynthesis. The enzyme glutamate-cysteine ligase (GCL) shows reduced efficiency with age, potentially due to homocysteine accumulation, impacting lifespan.
Area of Science:
- Biochemistry
- Cellular Biology
- Gerontology
Background:
- The cellular redox state, determined by the glutathione (GSH):oxidized glutathione (GSSG) ratio, shifts towards a pro-oxidizing environment during aging.
- This shift is attributed to increased GSSG levels and diminished capacity for de novo GSH synthesis.
Purpose of the Study:
- To investigate the impact of aging on the key enzyme in GSH biosynthesis, glutamate-cysteine ligase (GCL).
- To explore the role of homocysteine in age-related alterations of GCL function and its implications for aging.
Main Methods:
- Analysis of the K(m) of glutamate-cysteine ligase (GCL) during the aging process.
- Experimental studies examining the effect of homocysteine accumulation on GCL affinity for its substrates.
- Investigating the effects of GCL over-expression on lifespan in Drosophila models.
Main Results:
- The K(m) of GCL significantly increases with age, impairing rapid GSH biosynthesis, particularly under stress.
- Age-related homocysteine accumulation is implicated in reducing GCL's substrate affinity.
- Over-expression of GCL extended Drosophila lifespan by up to 50%.
Conclusions:
- Glutathione metabolism is critically involved in the aging process.
- Age-related decline in GCL function, potentially mediated by homocysteine, contributes to oxidative stress and aging.
- Modulating glutathione metabolism presents a potential therapeutic target for aging interventions.
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