Study of interaction between glutathione peroxidase mimics and substrates by surface plasmon resonance biosensor

The surface plasmon resonance (SPR) blosensor was designed on the basis of fixing the angle of incidence and measuring the reflected intensities. A charge coupled device (CCD) was used to measure the SPR spectra. Glutathione (GSH) self-assembling in solution was used to form the sensing membrane on the gold substrate. Interaction of glutathione-S-transferase (GST) and 2, 2-ditelluro bis-(2-deoxy-cyclodextrin) (2-TeCD) with substrate GSH were studied by this SPR sensor and the kinetic processes of sensing monolayer formation were studied. The kinetic constants of GSH and GST was 2.82 x 10(6) L/mol, GSH and 2-TeCD was 3.92 X 10(2) L/mol. These results validate the SPR sensor technology can be used to study interaction of the small-molecule glutathione peroxidase (GPX) mimics and substrate GSH in real time. Under the experimental conditions, the sensor is a labeling free, simultaneous observation of the interaction among enzyme and substrates can be realized and, therefore, kinetic constants of reactions can be obtained. Such instrumentation is to be used in fields such as on-line process monitoring.