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

Abstract

Incubated solutions containing glutathione (GSH) and a-or b-cyclodextrins (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 dissociation (CID) of the 1:1 and 1:2 (CD/GSH) and 1:1 (CD/GSSG) complexes reveals the strong interactions of the CDs with the peptides tested. The 1:2 (CD/GSH) complex is considered to be the oxidation reaction intermediate, which indicates that the three-dimensional structure of the complexed two GSHs in CD complexes is different from that of the proton-bound GSH dimer. The oxidation product, GSSG, is also observed in the CID spectrum of the singly charged 1:1 (CD/GSH) complex, suggesting that a complex ion-complex ion reaction occurs by forming a doubly charged complex dimer, as a result of the ability of ion trap to accumulate and activate ions. The observations indicate that ion trap mass spectrometry can be used to explore cyclodextrincatalyzed reactions and to carry out complex gaseous chemistry research.

Study on the intermediate ions formed by glutathione peroxidase mimic 2,2'‐ditellurobis(2‐deoxy‐β‐cyclodextrin) by electrospray ionization mass spectrometry

“…As shown in Fig. (a), the abundant single fragment peak at m/z 308 corresponds to protonated GSH and a minor peak at m/z 486 corresponds to the neutral loss (129 Da), which is a well‐documented neutral fragment (the N‐terminal Glu) of GSH, as reported previously …”

Electrochemical Studies of Inclusion Complex Formed Between Glutathione and β‐cyclodextrin‐modified Carbon Electrodes and its Application for Determination of Glutathione

“…A previously unused strategy is to modify the electrodes with β‐cyclodextrin (β‐CD), which is known to form inclusion complexes with GSH , allowing preconcentration of GSH at the electrode. In addition β‐CD catalyzes the chemical oxidation of GSH . β‐CD is composed of seven glucopyranose units joined in a ring, as shown in Figure B(a), forming a conical structure (as illustrated in Figure B(b)) with the winder side formed by the secondary hydroxyl groups and the narrower side by the primary hydroxyl groups .…”

“…A variety of compounds have been used to modify electrodes using several different methods ; however, often expensive reagents and complicated procedures are required . A previously unused strategy is to modify the electrodes with β‐cyclodextrin (β‐CD), which is known to form inclusion complexes with GSH , allowing preconcentration of GSH at the electrode. In addition β‐CD catalyzes the chemical oxidation of GSH .…”

Towards More Efficient Glutathione Peroxidase Mimics: Substrate Recognition and Catalytic Group Assembly

“…Analysis of the incubation solution containing GSH and cyclodextrin using electrospray mass spectrometry and tandem mass spectrometry reveals that cyclodextrin itself could bind with GSH to form an intramolecular complex [152]. Binding of GSH by a cyclodextrin derivative 6-OTs-6 -d e o x y -β -cyclodextrin was investigated by spectrophotometric titration and the binding constant was found to be 1.01x10 2 M [153].…”