Fluorescence Polarization of Human γG-Immunoglobulins^*

Quenching-resolved emission anisotropy studies with single and multitryptophan-containing proteins

“…The QREA method also offers some advantages over steady state anisotropy studies in which either temperature or bulk viscosity is varied. A problem with obtaining a Perrin plot by varying temperature is the possibility of having a temperature-induced conformational change or having thermally activated internal depolarizing motions (12,13,15). QREA studies can be performed at a series of fixed temperatures, thus allowing such temperature effects to be investigated.…”

“…Similar information concerning the motion of tryptophanyl residues (or other extrinsic probes) in proteins can be obtained from steady state measurements of emission anisotropy as a function of T/lq (10)(11)(12)(13)(14)(15). This approach is commonly used, but different results are often obtained depending on whether the experiments are performed by varying temperature or the bulk viscosity (see discussion in Concluding Remarks).…”

Phase behavior of mixed solution of a glycerin-modified cationic surfactant and an anionic surfactant

“…DPH is solubilized in the hydrophobic region of the bimolecular membrane and thus allows us to evaluate the microviscosity around DPH. Fluorescence polarization is correlated to the microviscosity near the fluorescent probe [26][27][28], which is calculated using PerrinWeber's equation [29,30]. An increase in fluorescence polarization corresponds to an increase in the microviscosity of the hydrophobic part of membrane.…”

The Antibody Problem

“…This model suggested that free, or unhindered, rotation of the three compact portions of the molecule was allowed, and it was pointed out that flexibility of this type would be advantageous for the precipitation of various antigens. This flexible model has to be reconciled, however, with an overall average rotational relaxation time of about 220 nsec measured by several methods (122)(123)(124)(125)(126)(127). This relaxation time is much greater than that of either the Fab or the Fc fragments.…”