Monitoring the Succinate Dehydrogenase Activity Isolated from Mitochondria by Surface Enhanced Raman Scattering†

Monitoring enzyme kinetics is an important aspect of biochemistry and is essential when studying metabolism. In this study we demonstrate that succinate dehydrogenase activity of mitochondria can be analyzed quantitatively by surface enhanced Raman scattering (SERS). We used the artificial electron acceptor reporter molecule 2,6-dichlorophenolindophenol (DCPIP) that when oxidized is SERS active. On reduction this redox dye changes from blue to colorless and is SERS inactive. This color change allows UV/vis spectrophotometry to be used as a standard reference measurement as well as SERS. SERS analysis incorporated kinetic time course measurements and employed a portable laser Raman spectrometer using an excitation wavelength of 785 nm in conjunction with gold colloids. Good correlation coefficients and quantitative data were observed with the additional advantage that analysis by SERS also provided good fingerprint spectral information from vibrational band frequencies thus allowing the potential of multiplexing enzyme reactions. We believe that this is the first demonstration of monitoring succinate dehydrogenase activity with SERS and that SERS has considerable potential for being applied to the analysis of metabolic processes.