Sglutathionylering

Sglutathionylering refers to a post-translational modification where glutathione, a tripeptide antioxidant, is covalently attached to a protein. This process is distinct from protein glutathionylation, which involves the formation of disulfide bonds with cysteine residues. Instead, sglutathionylering typically involves the formation of a thioester bond between the gamma-glutamyl carboxyl group of glutathione and an amino acid side chain on the target protein.

The functional significance of sglutathionylering is still an active area of research. It is hypothesized to play roles in protein stability, signaling pathways, and cellular defense mechanisms. Unlike glutathionylation, which is often reversible and involved in redox signaling, sglutathionylering may represent a more stable modification that alters protein function or targets proteins for degradation.

The enzymes responsible for catalyzing sglutathionylering are not fully characterized, though some studies suggest involvement of specific ligases. Detection and quantification of sglutathionylated proteins can be challenging due to the nature of the thioester bond and the potential for spontaneous hydrolysis. Techniques such as mass spectrometry are employed to identify and study these modifications. The precise cellular contexts and biological outcomes of sglutathionylering are subjects of ongoing investigation.