Kinetic studies of glutathione S-transferase-catalysed processes through on-line liquid chromatography–electrospray mass spectrometry

Abstract

Mass spectrometry is a sensitive and accurate technique for the direct monitoring of enzyme-catalysed reactions that does not require a chromophore or radiolabelling and thus provides a reliable alternative to the existing analytical approaches. In this study, the on-line technique high-pressure liquid chromatography (LC)–electrospray ionization (ESI) has been applied to the glutathione S-transferase-catalysed dehalogenation of haloaromatic compounds with the tripeptide glutathione, a process playing a central role in the catabolism of aromatic substrates in all living organisms. Attention has been focused on the relative leaving group mobility order of the halogen groups in benzene and napthalene systems.

Acknowledgements

We thank Mr A. Sterni for technical assistance in the LC–MS analysis; B.R. thanks Istituto Nazionale per la Fisica della Materia for financial support. This work was financially supported by MIUR–PRIN.