glutaredoxinmediated

Glutaredoxin-mediated refers to biochemical processes in which glutaredoxins catalyze thiol-disulfide exchange reactions using glutathione as an electron donor, thereby regulating the redox state of proteins and cellular pathways. Glutaredoxins (Grx) are small oxidoreductases within the thioredoxin superfamily found across bacteria, plants, and animals. They participate in deglutathionylation, the removal of glutathione from protein cysteine residues, and in the reduction of protein disulfides, contributing to redox homeostasis and signaling. Grx enzymes are generally categorized as monothiol or dithiol, distinguished by their active-site motifs; monothiol Grx typically feature a CGFS motif, while dithiol Grx use a CXXC motif, with variations observed among species.

In the catalytic cycle, a reactive cysteine in the Grx active site forms a transient mixed disulfide with substrate or with glutathione, enabling transfer of reducing equivalents. Regeneration of the active, reduced Grx often involves glutathione (GSH), producing oxidized glutathione (GSSG) in the process. Beyond deglutathionylation, some Grx enzymes participate in the assembly and delivery of iron-sulfur clusters, particularly in mitochondria and chloroplasts, linking redox chemistry to essential cofactors and metabolic pathways.

Biological significance of glutaredoxin-mediated reactions includes regulation of transcription factors, enzyme activity, and cellular responses to oxidative stress. Disruptions in glutaredoxin pathways can affect redox signaling and have been associated with aging, cancer, and neurodegenerative disorders. Overall, glutaredoxin-mediated processes constitute a central facet of glutathione-dependent redox regulation across diverse organisms.