Human serum albumin unfolding in ethanol/water mixtures was studied
by use of differential scanning calorimetry. Ethanol-induced changes in DSC
curves of defatted and non-defatted albumin were markedly different. In the
presence of ethanol, bimodal denaturation transition for fatty acid free albumin
was observed while that for albumin containing endogenous fatty acids was
single and more sharpen than in aqueous solution. Ethanol was found to decrease
the thermal stability of albumin due to the binding to the unfolded state
to a higher degree than to the native state, thus favouring unfolding. The
binding with different affinities has been suggested depending on ethanol
The effect of ethanol on human serum albumin stability in aqueous solution
was studied by use of differential scanning calorimetry. A deconvolution of
DSC traces in 2-state model with ΔCp=0
was performed and analysed to obtain information on the interaction of ethanol
with different parts of albumin molecule both fatty acid containing and fatty
acid free. The differences in ethanol binding affinity for both kinds of albumin
were found. At very low concentrations ethanol was observed to be a stabilizer
of the folded state of albumin contrary to the higher concentration where
its binding to the unfolded protein predominates.
Authors:G. Behbehani, A. Divsalar, A. Saboury, F. Faridbod, and M. Ganjali
Thermodynamics of the interaction between erbium(III) chloride, Er3+, with human serum albumin (HSA), was investigated at pH 7.0 and in phosphate buffer by isothermal titration calorimetry.
Our recently, solvation model was used to reproduce the enthalpies of HSA interaction by Er3+ over a broad range of metal ion concentration. The solvation parameters recovered from our new model, attributed to the structural
change of HSA and its biological activity. The binding parameters for the interaction of Er3+ and HSA indicate that the concentrations of Er3+ have no significant effects on the structure of HSA.
Human serum albumin microspheres were labelled with99mTc as a single step kit with radiochemical yields higher than 95%. With respect to the organ distribution in mice, the per cent of injected dose in liver was 78%.
Authors:K. Özker, A. Sungur, M. Ercan, N. Ardagil, and N. Aydin
The labelling of human serum albumin /HSA/ with99mTc has been investigated using a chemical method /stannous citrate/ and electrolytically generated tin/II/ ions. A comparative study of various chemical parameters and current intensities has been carried out in order to find the optimal conditions for labelling. The labelling yield was over 95%, for the chemical and electrolytical methods.
Authors:G. Rezaei Behbehani, A. Saboury, S. Tahmasebi Sarvestani, M. Mohebbian, M. Payehghadr, and J. Abedini
The thermodynamic parameters of interaction between theophylline and Human Serum Albumin (HSA) in buffer solution (30 mM)
of pH = 7 at 27 °C was investigated by isothermal titration calorimetry (ITC). The thermodynamic quantities of the binding
mechanism, the number of binding sites (g), the dissociation binding constant (Kd), the molar enthalpy of binding (ΔΗ) and other thermodynamic parameters can be obtained by the extended solvation theory.
Instrumental activation analysis was used to determine the contents of certain elements in human serum albumin (HSA). Sample
irradiation was performed with a thermal neutron flux of 1.5·1013 n·cm−2·sec−1 in the RA nuclear reactor of the Boris Kidrič Institute, Vinča. Measurements were performed on a 4096-channel analyser with
a high-resolution Ge(Li) detector. The Na, Cu, Br, Au, Hg, Cr, Fe, Ag, Sc, Ba and Co contents were determined in HSA produced
by the Institute for Blood Transfusion, Belgrade.
Authors:Elena Parfenyuk, Galina Kulikova, and Irina Ryabinina
Human serum albumin (HSA) adsorbed onto silica nanoparticles modified by 3-aminopropyltriethoxysilane (APTES) and polyethyleneimine
(PEI) was investigated by differential scanning calorimetry, IR spectroscopy, and photon correlation spectroscopy. The structural
alterations of the protein molecules induced from adsorption process were estimated on the basis of temperatures of denaturation
transition (Td) of the protein in free (native) and adsorbed form. It was found that adsorption of the protein onto the APTES-modified silica
nanoparticles results in an increase in the temperature of denaturation transition from 42 to 47.4 °C. HSA adsorbed onto the
PEI-modified silica nanoparticles unfolds extensively.
A multiple-site competitive model has been developed to evaluate quantitatively the equilibrium competition of drugs that bind to multiple classes of binding sites on human serum albumin (HSA). The equations, which are based on the multiple-class binding site model, assume that competition exists at individual sites, that the binding parameters for drug or drug competitor pertain to individual sites, and also that the binding parameters for drug or competitor at any given site are independent of drug or competitor bound at other sites. For the drug-competitor pairs, ethacrynic acid (EA) -caproic acid (C6), -lauric acid (C12), and -palmitic acid (C16), the reaction heat of EA binding to HSA was measured in the absence and the presence of fatty acids at the molar ratio of 3:1 with HSA at pH 7.4 and 37°C by isothermal titration microcalorimetry. The calorimetric titration data induced by the presence of fatty acids were directly compaired to the computer simulation curves by the corresponding multiple-site competititve models, which were precedently calculated from binding parameters of EA and fatty acids. In the case of EA-C12 or -C16 competitive binding, EA binding at the first and the second classes of binding sites on HSA were instantaneously inhibited by C12 or C16, resulting that the binding constant of the first class of binding sites of EA were decreased and that the second class of binding sites on HSA entirely disappeared. In the competition between EA and C6, the first class of binding sites of EA was diminished by C6, resulting in the decrease of the binding constants and the number of binding sites in the first class of EA, whereas, the second class of binding sites was unaffected. The multiple-site competitive model assuming site-site competition could be directly comparable to the calorimetric data and be suitable to account for the competitive processes for drugs bound to the multiple-class of binding sites on HSA.