The theoretical 77Se chemical shift as a probe of selenium state in selenoproteins and their mimics.

Theoretical 77Se chemical shifts of a series of simple organoselenium compounds are compared to known NMR data for various derivatives of selenoenzymes and selenoamino acids. Since the theoretical data only differs from the biochemical data set by an overall approximately 15-30 ppm downfield shift, simple theoretical model studies are suggested as an additional tool for the interpretation of selenoenzyme spectra. Further studies demonstrate that model systems can be extended to incorporate the effects of intramolecular interactions (such as Se.N bonds).