LC-MS and tandem MS as tools for the identification of enzyme-catalyzed reaction products

MAZZAFERRO LS; MULLER J; FRIES A; MULLER M; BRECCIA JD

Santa Rosa La Pampa

Congreso; 10th Congreso Argentino de Química Analítica; 2019

Departamento de Quimica FCEyN UNLPam - INCITAP

The fungal diglycosidase α-rhamnosyl-β-glucosidase catalyze transglycosylation reactions using alcohols and hesperidin, as sugar acceptors and donor, respectively1. In this work, the polyalcohols ethylene glycol and glycerol were used as sugar acceptors. Since glycerol and ethylene glycol contain multiple alcoholic groups, the formation of products was detected by liquid chromatography with mass spectrometry detection (LC-MS). For ethylene glycol as the sugar acceptor, one peak with the m/z value corresponding ethylene glycol rutinoside was observed. For glycerol as sugar acceptor, two signals could be observed with the m/z value mass corresponding to rutinosyl-glycerol. No signals were observed corresponding to the masses of di- and tri-rutinosylated products. Therefore, the α-rhamnosyl-β-glucosidase was capable of transglycosylate polyalcohols only once. To differentiate the two peaks corresponding to the mass of rutinosyl-glycerol, the MS/MS spectra were obtained. The spectra show, however, the same fragmentation pattern. The different retention times observed for these peaks, combined with their identical fragmentation pattern, suggest that these two peaks correspond to regioisomers; i.e., the primary or the secondary hydroxy groups could act as sugar acceptors.