N-->S phosphoryl migration in phosphoryl glutathion

Area of Science:

• Biochemistry
• Organic Chemistry
• Chemical Biology

Background:

• Glutathione plays a critical role in cellular redox homeostasis and detoxification.
• Phosphorylation is a key post-translational modification regulating protein function.
• Understanding phosphoryl migration mechanisms is crucial for studying enzyme activity and drug development.

Purpose of the Study:

• To investigate the mechanism of N-->S phosphoryl migration in glutathione derivatives.
• To elucidate the role of the intramolecular carboxyl group in catalyzing this migration.
• To differentiate between direct phosphorylation and migration pathways for thiol modification.

Main Methods:

• Utilized 31P-Nuclear Magnetic Resonance (31P-NMR) spectroscopy for tracing experiments.
• Synthesized and analyzed N-(diisopropylphosphoryl) glutathion (reduced form), N,N-bis(diisopropylphosphoryl) glutathion (oxidized form), and N-diisopropylphosphoryl cysteine.
• Performed competitive reaction studies involving amino and thiol groups with diisopropyl phosphite.

Main Results:

• Observed N-->S phosphoryl migration exclusively in N-(diisopropylphosphoryl) glutathion (reduced form).
• Demonstrated that phosphoryl migration was catalyzed by an intramolecular carboxyl group.
• Proposed a mechanism involving a mixed carboxyl-phosphoric anhydride intermediate.
• Confirmed that the phospho-thiol product did not arise from direct thiol phosphorylation.

Conclusions:

• The reduced form of N-(diisopropylphosphoryl) glutathion undergoes intramolecular N-->S phosphoryl migration.
• The carboxyl group is essential for catalyzing this migration, proceeding through a mixed anhydride.
• N,S-Bis(diisopropylphosphoryl) glutathion serves as a key standard for identifying the migrated product.