[Polarization of intrinsic fluorescence of proteins. IV. Changes in the degree of polarization from the emission spectra].
A smooth decrease of the fluorescence emission polarization as the wavelength of registration increases along the emission spectrum was determined for some proteins and also for tryptophan, N-acetyl-tryptophan and glycyl-tryptophan. Various factors that can explain the way of the curve were analysed. A special attention was paid to the problem of the possibility of the 1Lb oscillator participation in the emission. It is shown that in the case of dual fluorescence emission from both 1La and 1Lb states the position and the shape of polarized components of emission spectrum and the magnitude of the ratio r320/r365, that characterizes the slope of the curve P = f(lambda em), must always depend upon lambda ex. Nevertheless it is shown that the dependences of r320/r365 upon lambda ex, found for some proteins are explained by the contribution of tyrosine residues into emission and there are no reasons to assume the participation of the 1Lb oscillator in the emission (even in the case of the proteins with shortwave spectrum position as L-asparaginase). It is shown that the slope of the curve in the case of individual emission centres is determined by the alteration of the electronic states between which the transition accompanied by the emission takes place. Heterogeneity of the fluorescence centres, that are to some or other extent inherent to proteins, also can influence the slope of the curve P = f (lambda em).
K K
KK
Turoverov
I M
IM
Kuznetsova
D000818:Animals; D002417:Cattle; D005453:Fluorescence; D005454:Fluorescence Polarization; D006801:Humans; D004676:Myelin Basic Protein; D011506:Proteins; D012710:Serum Albumin, Bovine; D013050:Spectrometry, Fluorescence
D004676:Myelin Basic Protein; D011506:Proteins; D012710:Serum Albumin, Bovine
Poliarizatsiia sobstvennoĭ fluorestsentsii belkov. IV. Izmenenie stepeni poliarizatsii po spektru izlucheniia.