Kinetic Studies on Decomposition of Glutathione. II. Anaerobic Decomposition in Aqueous Solution

抄録

Kinetics studies were performed on the non-enzymatic decomposition of glutathione (GSH) in anaerobic aqueous solution. The apparent first-order rate constants of decomposition were determined in the pH range of 1-12, ionic strength 0.5, at 60° and the pH profile was constructed from the buffer-free rate constants and pH values. The decomposition of GSH took place rapidly in acidic solution, but the rate constant showed a minimum in the pH range of 5-6, a maximum at pH 8.5 and a plateau in the pH range of 10-12. The effects of ionic strength and dielectric constant were almost negligible. The apparent activation energies of decomposition of GSH were all in the range of 19-21 kcal/mol. The rate constants of decomposition were related to the mole fractions of ionic species of GSH, and could be expressed as a function of hydrogen ion activity at arbitrary pH.