[Polarization of intrinsic fluorescence of proteins. II. Application for the study of equilibrium dynamics of tryptophan residues].

Additional support of some statements essential for interpretation of the data obtained by the rotational depolarization technique is given. They are: (i) after excitation at the red edge of absorption band of tryptophan there occurs no intertryptophan excitation energy transfer, (ii) at the red edge excitation 1La is the only excited state involved in absorption and emission processes, and (iii) the polarization value (PoCa, 0,256) experimentally measured for some model compounds retains to be consistent also for tryptophan residues in proteins and is independent of the polarity of their microenvironment. An attempt is made to prove possibility of intermolecular rotational mobility of the tryptophanyl indole rings inside the protein globule during the excited state lifetime.