Effect of Glycation of Hemoglobin on its Interaction with Trifluoperazine (original) (raw)
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Zenodo (CERN European Organization for Nuclear Research), 2020
Studies on the interaction of drugs with bio-macromolecules have been of great interest to understand the molecular aspects of such binding correlating with the structural phenomenon. The binding interaction of a well-known antibiotic drug, Sulfamethazine (SMZ) towards hemoglobin (Hb) have been studied extensively using fluorescence spectroscopic technique. The temperature dependent experiments suggested static quenching and ground state complex formation with the number of binding sites around 1 signifying 1:1 binding ratio with the protein. The thermodynamic parameters obtained from the temperature dependent analyses conveyed entropy driven spontaneous, exothermic reaction. The negative enthalpy and a strong positive entropy contribution suggested dominance of electrostatic force(s) between the protein and the drug. The salt dependent analyses denoted destabilization of the complex with increase in the ionic strength, thus signifying decrease in the electrostatic interaction between Hb and SMZ which is in accordance with the thermodynamic calculations. The partition of free energy change concluded non-polyelectrolytic components to be the dominant factor in the bending between the protein and the drug.
The characterization of modified human hemoglobin. II. Reaction with 1-fluoro-2,4-dinitrobenzene
The Journal of biological chemistry, 1968
A dinitrophenyl derivative of human hemoglobin has been prepared and purified, in which the only site of reaction is the NH2 terminus of the (Y cl ain. Evidence for this comes from two sources: first, the identification of all of the tryptic peptides having absorption at 355 rnl.c; second, from experiments with 14C-labeled I-fluoro-2,4dinitrobenzene which show that the stoichiometry of the reaction is 1 dinitrophenylgroup per a/3 subunit. Competition experiments with iodoacetamide show that 1-fluoro-2,4dinitrobenzene does not react with the "reactive" sulfhydryl group on the fl chain. This single substitution leads to quite drastic physical and functional changes. The modified hemoglobin has an increased oxygen aiBnity, an R value of 1 in the Hill equation, and no Bohr effect. In all dissociating solvents tested, the dinitrophenyl-hemoglobin is more highly associated than native hemoglobin.
Journal of Solution Chemistry, 2011
The interactions of colchicine (COL) and aspirin (ASA) with human hemoglobin (HB) was studied by fluorescence, UV/vis absorption, resonance light scattering, synchronous fluorescence and circular dichroism (CD) spectroscopic techniques under physiological conditions. The inherent binding information, including the quenching mechanism, binding constants, number of binding sites, effective quenching constant, fraction of the initial fluorescence and thermodynamic parameters were determined by the fluorescence quenching technique at different temperatures. The results proved that the mechanism of fluorescence quenching of HB by COL and ASA is due to formation of HB-drug complexes in the binary and ternary systems. The distance between the acceptor drugs and HB was estimated by Förster's equation on the basis of fluorescence energy transfer. In addition, according to the synchronous fluorescence spectra of HB, the results showed that the fluorescence quenching of HB originated solely from the tryptophan residues and indicated a conformational change for HB caused by addition of the drugs. Far-UV CD spectra of HB were recorded before and after the addition of ASA and COL both as binary and ternary systems. An increase in intensity of the positive CD peak of HB was observed in the presence of these drugs. The results were interpreted as excited state interactions between the aromatic residues of the HB binding sites and the drugs bound to them.
International Journal of Biological Macromolecules, 1998
Binding modalities of chlorpromazine and trifluoperazine, two widely used antipsychotic phenothiazine drugs with hemoglobin and myoglobin have been studied to understand how the quaternary, tertiary and secondary structural organisations of the proteins regulate the binding process. NaCl-induced alteration in the quaternary structure of hemoglobin influences its binding modality with phenothiazines. Minor alterations in the tertiary structure of thermally denatured myoglobin (denaturation temperature ranging between 30-70 degrees C) do not affect its affinity and the modality of binding with the drugs, but alterations in the secondary structure of the protein denatured at temperatures between 70-80 degrees C influence its binding.
Journal of Inorganic Biochemistry, 1998
In the present study, the effect of the neuroleptics chlorpromazine (2-chloro-N,N-dimethyl-10H-phenothiazine-10-propanamine) and trifluoperazine o10-[3-(4-methylpiperazin-1-yl)-propyl]-2-(trifluoromethyl)-10H-phenothiazineq on the EPR-spectroscopic properties of ferrous human adult nitrosylated haemoglobin (HbNO) is reported. Addition of the two drugs to HbNO shifted the conformational equilibrium from the high-to the low-affinity form of the ligated tetramer, as observed for 2,3-D-glycerate bisphosphate, the physiological modulator of haemoglobin action. The effect of chlorpromazine and trifluoperazine on the EPR-spectroscopic properties of HbNO was enhanced by inositol hexakisphosphate. The binding of neuroleptics to ferrous human adult haemoglobin may represent an important undesirable side effect. In fact, oxygen affinity for ferrous human adult haemoglobin decreases on increasing chlorpromazine and trifluoperazine concentration. In addition, red blood cells may act as neuroleptic scavengers.
Structural alterations of hemoglobin and myoglobin by glyoxal: A comparative study
International Journal of Biological Macromolecules, 2014
Glyoxal, a highly reactive oxoaldehyde, increases in diabetic condition. It reacts with different proteins to form advanced glycation end products (AGEs). Here we have studied the structural alterations as well as the sites and nature of amino acid modifications of two heme proteins, hemoglobin and myoglobin on incubation with glyoxal for seven days at 25 • C. In comparison with normal hemoglobin (HbA 0), glyoxal-treated hemoglobin (GHbA 0) exhibits decreased absorbance around 280 nm, reduced intrinsic fluorescence and lower surface hydrophobicity. However, glyoxal-treated myoglobin (GMb) exhibits the opposite effects in these respects when compared to normal myoglobin (Mb). Glyoxal increases the thermal stability of hemoglobin, while it decreases the stability of myoglobin. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF)-mass spectrometry reveals modifications of Arg-31␣, Arg-40 and Arg-104 of hemoglobin by glyoxal to hydroimidazolone adducts. On the other hand, glyoxal modifies Lys-133 and Lys-145 to carboxymethyllysine and Arg-31 to hydroimidazolone adducts in myoglobin. Thus the same oxoaldehyde exerts different effects on hemoglobin and myoglobin and may be associated with different structural properties of the proteins.
Contribution of trifluoperazine/lipid ratio and drug ionization to hemolysis
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1998
The interaction of the antipsychotic drug trifluoperazine (TFP) with membranes was investigated in terms of lipid phase perturbation. TFP partition coefficients (P) were measured by phase separation between octanol/water and model membranes/water. The profile of P values at pH 7.4 was: microsomes (7172+ 1229) > liposomes (1916+ 341) > erythrocyte ghosts (1380_+429)> octanol (452_+55). Hemolytic experiments showed a biphasic, protective (at lower concentrations) and hemolytic effect above the CMC (42 ~tM at pH 7.4) of the phenothiazine. By applying classical treatments for surface active compounds to the hemolytic curves, we could calculate P values in whole erythrocyte cells. The preferential binding of uncharged to charged TFP in the membrane was discussed, since it results in a ionization constant (pKapp) different from that observed in the aqueous phase (pK). The TFP ionization constant was decreased from 8.1 (in water) to 7.62 in the presence of membranes and almost the same ratio of charged/uncharged TFP species is present at physiologic pH. Taking into account the ApK, we calculated the average TFP partition coefficient between egg phosphatidylcholine liposomes and water, at pH 7.4 (P ..... ge = 1432), which was well correlated with the measured one (plip= 1916). Paverage is highly influenced by the uncharged TFP species and the real base/acid ratio under physiologic conditions was discussed in terms of its possible role in the biological activity of TFP.
Properties of normal and glycated human hemoglobin in presence and absence of antioxidant
Biochemical and Biophysical Research Communications, 2005
We present a novel approach to study properties of normal (HbA) and nonenzymatically glycated (HbA Ic , HbA Ia+b ) human hemoglobin using absorption spectroscopy and differential scanning calorimetry. The effect of the presence of the antioxidant fisetin on glycation of HbA is studied. Here, absorption spectroscopy has been fruitfully exploited to observe the formation of the glycated hemoglobin. With the differential scanning calorimetry, we studied the thermal unfolding of the protein hemoglobin at various conditions. The thermogram of the pure HbA showed two transition regions, with the occurrence of a partially unfolded intermediate state (the formation of which is mainly reversible) prior to complete denaturation (irreversible process). The denaturation temperature of HbA was found to be strongly dependent on the heating rate. Furthermore, there is a significant cooperativity between the two transition regions in pure HbA. The overall denaturation for the glycated hemoglobin takes place at a lower temperature, suggesting a decrease in the stability of the protein when it is glycated. In presence of fisetin, glycation is inhibited to a certain extent and the thermograms match well with that of normal HbA. Implications of the results are discussed.