Cyclodextrin-catalyzed oxidation of glutathione in solution and in an ion trap

Incubated solutions containing glutathione (GSH) and alpha- or beta-cyclode xtrins (CDs) were analyzed using electrospray mass spectrometry and tandem mass spectrometry, The results suggest that both CDs can catalyze oxidation of GSH to the oxidized glutathione (GSSG). The collision-induced dissociat ion (CID) of the 1:1 and 1:2 (CD/GSH) and 1:1 (CD/GSSG) complexes reveals t he strong interactions of the CDs with the peptides tested. The 1:2 (CD/GSH ) complex is considered to be the oxidation reaction intermediate, which in dicates that the three-dimensional structure of the complexed two GSHs in C D complexes Is different from that of the proton-bound GSH dimer, The oxida tion product, GSSG, Is also observed in the CID spectrum of the singly char ged 1:1 (CD/GSH) complex, suggesting that a complex ion-complex ion reactio n occurs by forming a doubly charged complex dimer, as a result of the abil ity of ion trap to accumulate and activate ions. The observations indicate that ion trap mass spectrometry can be used to explore cyclodextrin-catalyz ed reactions and to carry out complex gaseous chemistry research. Copyright (C) 1999 John Wiley & Sons, Ltd.