Abstract
S-glutathionylation, the reversible formation of a mixed disulfide bridge between a specific cysteine and a glutathione molecule, can occur spontaneously or be catalyzed by enzymes. Glyoxalase II (GloII), using its natural substrate SLG can form specific protein-SSG mixed disulfide leading enzymatic regulation of S-glutathionylation.
1. Introduction
Glyoxalase II (Glo2), the second enzyme of Glyoxalase system, is an antioxidant glutathione-dependent enzyme, that catalyzes the hydrolysis of S-D-lactoylglutathione (SLG) to form D-lactic acid and glutathione (GSH) []. GSH is the most important thiol-reducing agent inside the cell. Due to its chemical features, GSH plays a crucial role not only in the cellular redox state but also in various cellular processes including protein S-glutathionylation. S-glutathionylation a process that involves the reversible formation of a mix disulphide-bridge between specific cysteine residues, and GSH can be spontaneous or catalyzed by an enzyme. S-Glutathionylation is also involved in the protection of protein thiol groups from irreversible oxidation and plays key role in redox regulation by activation/inactivation of different enzymes.
2. Methods
Glo2 and SLG were incubated with different proteins that are known to be glutathionylated, such as malate dehydrogenase, actin or cytochrome c purified proteins [].
3. Results
During the hydrolysis of SLG, in the active site of Glo2 there is unprotonated glutatione molecule (GS-) which can be transferred to protein target []. These in vitro studies demonstrate the high propensity of Glo2 to aggregate with other proteins through its catalytic site, leading to an enzymatic regulation of S-glutathionylation in proteins of different origin and cellular compartmentalization.
4. Conclusions
Identification of active involvement of Glo2 in glutathionylation of different proteins. In this perspective, Glo2 can play a new important regulatory role in S-glutathionylation, acquiring further significance in cellular post-translational modifications of protein.
Supplementary Materials
The following are available online at https://www.mdpi.com/2673-9992/2/1/7/s1.
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