Interaction of chlorpromazine with myoglobin and hemoglobin: A comparative study
TL;DR: Thermodynamic analysis revealed that binding of CPZ to hemoglobin was exothermic, whereas binding to myoglobin was endothermic with a high entropic contribution, suggesting that CPZ binding toMyoglobin is hydrophobic in nature.
About: This article is published in Biochemical Pharmacology.The article was published on 1994-06-01. It has received 68 citations till now. The article focuses on the topics: Myoglobin & Binding constant.
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TL;DR: In this article, an acidic tea polysaccharide (TPSA) was isolated from green tea and a Congo red residue-conjugated TPSA derivative (CR-TPSA), which showed positive zeta potentials and irregular spherical nanoparticles in the sizes of 50-100 nm.
Abstract: Tea polysaccharides exhibit multiple important bioactivities, but very few of them can be absorbed through the small intestine. To enhance the absorption efficacy of tea polysaccharides, a cationic vitamin B12-conjugated glycogen derivative bearing the diethylenetriamine residues (VB12-DETA-Gly) was synthesized and characterized using FTIR, 1H NMR, and UV-vis spectroscopy. An acidic tea polysaccharide (TPSA) was isolated from green tea. The TPSA/VB12-DETA-Gly complexed nanoparticles were prepared, which showed positive zeta potentials and were irregular spherical nanoparticles in the sizes of 50–100 nm. To enable the fluorescence and UV-vis absorption properties of TPSA, a Congo red residue-conjugated TPSA derivative (CR-TPSA) was synthesized. The interactions and complexation mechanism between the CR-TPSA and the VB12-DETA-Gly derivatives were investigated using fluorescence spectroscopy, resonance light scattering spectroscopy, and UV-vis spectroscopy. The results indicated that the electrostatic interaction could play a major role during the CR-TPSA and VB12-DETA-Gly-II complexation processes. The TPSA/VB12-DETA-Gly nanoparticles were nontoxic and exhibited targeted endocytosis for the Caco-2 cells, and showed high permeation through intestinal enterocytes using the Caco-2 cell model. Therefore, they exhibit potential for enhancing the absorption efficacy of tea polysaccharides through the small intestinal mucosa.
5 citations
TL;DR: The conformation and thermodynamics of α-amylase interaction with ethylene in vitro were investigated and the calculated values of ΔH(0) and ΔS( 0) are positive, which suggests that the interaction between ethylene and α-AMylase is an endothermic reaction.
Abstract: In this article, the conformation and thermodynamics of α-amylase interaction with ethylene in vitro were investigated. The ultraviolet (UV) absorption showed a strong peak of α-amylase treated with 6.04, 29.32 and 262.11 μmol L − 1 ethylene appears at ~ 222 nm and a weak peak at 278 nm blue-shifted 1 nm. Circular dichroism (CD) spectra indicated that the conformations of α-amylase treated with 29.32 and 262.11 μmol L − 1 ethylene were obviously changed in which α-helix content were decreased by 20 and 31% respectively, and β-sheet, β-turn and random coil contents were increased by contrast. Fluorescence spectra suggested that the peak intensities of α-amylase at 342 nm were obviously increased with the ethylene increase from 6.04 to 525.75 μmol L − 1 and more than control group. The binding constants K between ethylene and α-amylase were 3.318 × 10 6 , 4.407 × 10 6 and 5.125 × 10 6 L mol − 1 at 288, 298 and 308 K, respectively. And the calculated values of ΔH 0 and ΔS 0 are positive, which suggests that the interaction between ethylene and α-amylase is an endothermic reaction. The negative ΔG 0 values implied that the direct effect of ethylene on α-amylase conformation was spontaneous. The possible reason is that ethylene molecules were easily embedded into the interior of α-amylase in term of the hydrophobic force between α-amylase and ethylene, causing the conformation and thermodynamics changes of α-amylase.
4 citations
TL;DR: A comparison of the interaction mechanisms for CPTC/PCTA-proteins/DNA systems have been performed in view of their different molecular structures, which is beneficial for the further research in order to design them as the novel drugs.
4 citations
TL;DR: Hematoporphyrin potentiates horseradish peroxidase-catalyzed H2O2-mediated NADH oxidation, probably by porphyrIn-influenced removal of superoxide radicals, which are generated in the system.
3 citations
TL;DR: Experimental results indicate that Cr(NN) 3 3+ binds to serum albumins, by which these proteins could act as carriers of this complex for further applications in PDT.
Abstract: We report a detailed investigation of the interaction of Cr(NN)33+ with bovine serum albumin (BSA), an important protein for the transport of drugs in blood plasma which allows us to understand further the role of Cr(NN)33+ as a sensitizer in photodynamic therapy (PDT). Chromium(III) complexes, Cr(5Cl-phen)33+, Cr(5Me-phen)33+ and Cr(5Ph-phen)33+ (where Cl = chlorine, Me = methyl and Ph = phenyl are substituents in position 5 of the phen = 1,10-phenanthroline bidentate ligand), were used for the present study. The interactions of BSA with Cr(NN)33+ were assessed employing fluorescence spectroscopy and UV–Vis absorption spectroscopy; in addition electrochemical experiments carried out at a liquid/liquid interface gave insight into the relative hydrophobicities of the complexes. We found that chromium complexes bind strongly with bovine serum albumins (BSA) with intrinsic binding constants, Kb, of (3.33 ± 0.08) × 105 M−1, (5.92 ± 0.08) × 105 M−1 and (1.64 ± 0.05) × 105 M−1 at 300.3 K. Analysis of the thermodynamic parameters ΔG, ΔH, and ΔS indicated that hydrophobic interactions played a major role in all the BSA-Cr(NN)33+ association processes. The binding distances and transfer efficiencies for BSA binding reactions were calculated according to the Forster theory of non-radiation energy transfer giving distance (r) of 2.63 nm, 2.94 nm and 3.00 nm for 5Clphen, 5Mephen and 5Ph phenanthroline complexes, respectively. All these experimental results indicate that Cr(NN)33+ binds to serum albumins, by which these proteins could act as carriers of this complex for further applications in PDT.
2 citations
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534 citations
TL;DR: Binding of chlorpromazine with human hemoglobin has been studied by equilibrium dialysis and fluorescence quenching and results revealed that the binding was positively cooperative with overall affinity constant K = 3.8 x 10(3) M-1.
102 citations
TL;DR: This chapter presents procedures for the isolation of intracellular oxygen-binding proteins of tissues, called “tissue hemoglobins” in the widest sense, which are monomers or dimers having a minimum molecular weight of 18,000 with similar optical spectra and chemical reactivity.
Abstract: Publisher Summary This chapter presents procedures for the isolation of intracellular oxygen-binding proteins of tissues, called “tissue hemoglobins” in the widest sense. All of these, except Ascaris and yeast hemoglobin, are monomers or dimers having a minimum molecular weight of 18,000 with similar optical spectra and chemical reactivity. Strictly, only muscle hemoglobin should be called “myoglobin”; by extension the term is often applied to other tissue hemoglobins as well. Ferric myoglobin may be purified by chromatography on carboxymethyl (CM) cellulose, usually at slightly acid pH or on diethylaminoethyl (DEAE) cellulose. The choice of preparative procedure depends on the use to which the purified myoglobin will be put. Both DEAE and CM ion-exchange columns yield myoglobin that is pure in the sense of being free from contaminating polypeptide chains. Better resolution of forms of myoglobin differing only in charge is achieved on CM-cellulose. Such columns, however, are usually operated at acid pH, and it is a matter of experience that oxymyoglobin exposed to mildly acidic conditions becomes ferric and, in the process, undergoes some minor but apparently irreversible change. The chapter also explains the isolation and purification of vertebrate myoglobins.
75 citations
TL;DR: The irreversible binding of chlorpromazine radical cation (CPZ+.) and photoactivated chlor Promazine ( CPZ) to calf thymus DNA in vitro and bacterial macromolecules in intact bacterium cells was investigated and the consequences of covalent binding for the cytotoxicity and genotoxicity of CPZ+.
39 citations
TL;DR: Scatchard analysis indicates that all four ligands are true agonists of the receptor exhibiting positive cooperative binding with the existence of more than one class of binding site.
29 citations