Application of phosphorescence to the study of proteins

This chapter provides information on the application of phosphorescence to the study of proteins. The use of phosphorescence for studying problems of protein structure and protein-ligand interaction is illustrated by reference to a number of recent investigations. There is much in common in the rationale behind the techniques of phosphorescence and fluorescence. Because excellent reviews are available on the instrumentation and methodology of fluorescence measurements as well as on various aspects of the phosphorescence technique, the chapter limits the discussion to a description of the components of a phosphorescence accessory and the special problems involved in carrying out a phosphorescence measurement. The complete characterization of phosphorescence requires the determination of the emission and excitation spectra, the phosphorescence yield, the lifetime of the excited state, and the polarization of the phosphorescence. Some of these parameters are readily obtainable. Others, particularly phosphorescence polarization, are very difficult to determine.