EPR and circular dichroism solution studies on the interactions of bovine serum albumin with ionic surfactants and β-cyclodextrin.

The interactions of bovine serum albumin (BSA) with ionic surfactants (sodium dodecyl sulfate, SDS, and cetyltrimethylammonium bromide, CTAB) and β-cyclodextrin (β-CD) have been investigated by electron paramagnetic resonance (EPR) and circular dichroism measurements. The spin probe selected to report on the interaction of albumin with surfactants and/or β-CD was 4-N,N-dimethyl hexadecyl ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl iodide (CAT16), on account of (a) its balance between electrostatic and hydrophobic character and (b) the ability of BSA to form complexes with various organic molecules. The distribution of the spin probe among different environments in solutions containing only BSA was confirmed by the existence of two components in the EPR spectra: one revealing a restricted mobility of the spin probe, attributed to the protein-spin probe complex, and another one showing free movement, attributed to the spin probe in solution.

Spectral and interferometrical study of the interaction of haemin with glutathione.

The interaction of haemin with reduced glutathione (GSH) was investigated in vitro and the association constant was determined by both spectrophotometric and interferometric methods. In order to elucidate the nature of this interaction, the reaction of haemin with a typical reductive agent (sodium dithionite) and a typical chelating agent for hem-iron (histidine) was also studied. Haemin-induced haemolysis in the presence and absence of GSH was monitored spectrophotometrically.

Structure/nerve membrane effect relationships of some local anaesthetics.

Data on electron structure and octanol-water partition coefficients of certain local anaesthetics are compared with the capacity of reversibly block the action potential of the frog sciatic nerve. Some active parts in the molecules of these substances have been shown to be primarily involved in the action of local anaesthetics.