COMPARED REACTIVITIES OF TRYPANOTHIONE AND GLUTATHIONE IN CONJUGATIONREACTIONS

In order to compare the non-enzymatic capacities of the xenobiotic con jugation of trypanothione (a spermidine-glutathione conjugate unique t o kinetoplastidae) and glutathione, the reactivity of their respective thiols was investigated. The acido-basic properties of both compounds and their nucleophilicity toward Ellman's reagent and 1-chloro-2,4-di nitrobenzene were studied. Our results show that although glutathione is a better nucleophile than trypanothione, the latter is more reactiv e because it is more ionized in a large pH range. This pH range likely includes the pH to which such conjugation reactions are expected to h appen in vivo. Thus, the better conjugation capacity of trypanothione could make it the cornerstone for the xenobiotic detoxication of trypa nosomatidae.