ABSTRACT
A microspectrofluorimeter which permits recording excitation and emission spectra of fluorescent dyes (fura-2, indo-1) and measuring Ca(2+)-transients in different cells and smooth muscle strips is described. One-beam and two-beam approaches of recording of spectral characteristic of fluorescent dyes are presented.
Subject(s)
Calcium/metabolism , Cells/metabolism , Animals , Equipment Design , Fluorescent Dyes , Muscles/metabolism , Spectrometry, Fluorescence/instrumentation , Spectrometry, Fluorescence/methodsABSTRACT
Fluorescent properties of indo-1 in protein containing solutions have been investigated. No changes have been defined in indo-1 fluorescent parameters in solutions of such proteins as trypsin, calmodulin, papain, lysozyme. Significant changes of indo-1 fluorescent parameters have been observed in solutions of histones, bovine and human serum albumins. Results obtained suggest that indo-1 binds well with protein sites containing hydrophobic "pockets" and positively charged amino-acid residues such as arginine and lysin. The destruction of the compact structure of serum albumin in 8 M urea leads to shift of indo-1 fluorescence spectrum and it approaches to the spectrum in water. Fluorescence spectra of indo-1 in dioxane prove that the binding of indo-1 by some proteins occurs in hydrophobic microenvironment of protein globule.
Subject(s)
Fluorescent Dyes , Indoles , Proteins/chemistry , Animals , Calmodulin/chemistry , Cattle , Culture Media , Histones/chemistry , Humans , Ions , Muramidase/chemistry , Papain/chemistry , Serum Albumin/chemistry , Serum Albumin, Bovine/chemistry , Spectrometry, Fluorescence , Trypsin/chemistryABSTRACT
Flavonoids (quercetin, rutin) influence ATPase activity and actomyosin superprecipitation. Low concentrations (below 20 mumol/l) of flavonoids were found to cause conformational changes in the myosin structure accompanied by an increase in ATPase activity. At higher concentrations an inhibitory action of flavonoids on both ATPase activity and actomyosin superprecipitation occurred. Conformational changes are likely to be due to flavonoids binding to regulatory site near the active centre of the myosin head. The effect of quercetin was stronger than that of rutin.
