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Journal ArticleDOI

Evidence for cooperative binding of chlorpromazine with hemoglobin: equilibrium dialysis, fluorescence quenching and oxygen release study.

30 Mar 1990-Biochemical and Biophysical Research Communications (Academic Press)-Vol. 167, Iss: 3, pp 1146-1153
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.
About: This article is published in Biochemical and Biophysical Research Communications.The article was published on 1990-03-30. It has received 102 citations till now. The article focuses on the topics: Quenching (fluorescence) & Fluorescence spectrometry.
Citations
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Journal ArticleDOI
TL;DR: The synchronous fluorescence, CD and three-dimensional fluorescence spectral results showed that the hydrophobicity of amino acid residues increased and the losing of α-helix content in the presence of PAAB revealed that the microenvironment and conformation of BSA were changed in the binding reaction.
Abstract: In this paper, the interaction between p-aminoazobenzene (PAAB) and BSA was investigated mainly by fluorescence quenching spectra, circular dichroism (CD) and three-dimensional fluorescence spectra under simulative physiological conditions. It was proved that the fluorescence quenching of BSA by PAAB was mainly a result of the formation of a PAAB-BSA complex. The modified Stern-Volmer quenching constant Ka and the corresponding thermodynamic parameters ΔH, ΔG and ΔS at different temperatures were calculated. The results indicated that van der Waals interactions and hydrogen bonds were the predominant intermolecular forces in stabilizing the complex. The distance r = 4.33 nm between the donor (BSA) and acceptor (PAAB) was obtained according to Forster’s non-radioactive energy transfer theory. The synchronous fluorescence, CD and three-dimensional fluorescence spectral results showed that the hydrophobicity of amino acid residues increased and the losing of α-helix content (from 63.57 to 51.83%) in the presence of PAAB. These revealed that the microenvironment and conformation of BSA were changed in the binding reaction.

334 citations


Cites background from "Evidence for cooperative binding of..."

  • ...Fluorescence quenching refers to any process which decreases the fluorescence intensity of a sample such as excited state reactions, energy transfers, ground-state complexes formation and collisional process [16]....

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Journal ArticleDOI
TL;DR: Results suggest that the primary binding site for methyl parathion on albumin is close to tryptophan residues 214 of human serum albumin and 212 of bovine serum albumIn, and suggest that this pesticide is potentially toxic for both vertebrates and invertebrates.

204 citations


Cites background from "Evidence for cooperative binding of..."

  • ...The quenching can be mathematically expressed by the Stern–Volmer equation, which allows for the calculating of quenching constants (Bhattacharyya et al., 1990)....

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  • ...Determination of quenching type, however, requires the additional examination of temperature dependence of the quenching process (Bhattacharyya et al., 1990; Lakowicz, 1999)....

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  • ...Indeed, the observation on the behaviour of Stern–Volmer curves as we vary temperature, may indicate the nature of phenomenon causing quenching, as well as by measurements of florescence lifetime (Bhattacharyya et al., 1990; Lakowicz, 1999)....

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Journal ArticleDOI
TL;DR: The results suggest the prime binding site for CPZ and Hmn on both HSA and BSA to be near tryptophan residues, an important ferric residue of hemoglobin that binds within the hydrophobic region of albumin with great specificity.

110 citations

Journal ArticleDOI
TL;DR: In this article, the binding reaction between riboflavin (RF) and bovine serum albumin (BSA) was studied by using fluorescence spectra and absorption spectra.

109 citations

Journal ArticleDOI
TL;DR: The interaction of a food colourant, quinoline yellow (Qy), and bovine serum albumin (BSA) was investigated by spectrophotometry, spectrofluorometry, FT-IR and circular dichroism techniques and indicated that the quenching mechanism of BSA by the dye was a static procedure.

105 citations

References
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Journal ArticleDOI
TL;DR: It is concluded that small-molecule amphipaths, at concentrations lower than lytic, promote gross redistributions of components in the plane of a membrane that result in the observed extractions.
Abstract: In their interactions with membranes, amphipathic small molecules exhibit detergent-like properties. At sufficiently high concentrations (above their critical micelle concentrations, if they form micelles), they substantially dissolve membranes. At lower concentrations, between maximally antihemolytic and lytic, we show here that the amphipaths significantly perturb membrane structure. Each of six small-molecule amphipaths was shown by hygroscopic desorption filtration to induce the extraction of small but significant amounts of membrane components, partly in the form of vesicular fragments, from red blood cell membranes. These extracts were enriched in the lipid to protein ratio as compared to the intact membrane, and the protein composition was highly unrepresentative. A similar set of extractions from sarcoplasmic reticulum membranes was induced by the six amphipaths. We conclude that small-molecule amphipaths, at concentrations lower than lytic, promote gross redistributions of components in the plane of a membrane that result in the observed extractions.

79 citations

Journal ArticleDOI
TL;DR: It is taken as evidence that the inner leaflet of the bilayer is the seat for the observed multiphasic changes of viscosity and the control of adenylate cyclase and catecholamine receptors.
Abstract: The fluorescence anisotropy probe perylene and the spin-labels 5-doxylsterate and 16-doxylstearate were used to estimate the order and internal microviscosity of the pigeon erythrocyte membrane upon perturbation by cationic or neutral amphipathic drugs (chlorpromazine, methochlorpromazine, tetracaine, and octanol) and an anionic drug, octanoic acid. Both methods gave identical results. The fluidity changes were found to strictly correlate with those of adenylate cyclase activity in the presence of GTP when perturbed by the drugs [Salesse, R., & Garnier, J. (1979) Biochim. Biophys. Acta 554, 102-113]. The cationic or neutral drugs, in an intermediate range of concentration, decreased the degree of organization and the internal microviscosity of the lipids together with the activity of the adenylate cyclase. At a higher concentration they reincreased them up to or higher than their initial level before the final destruction of the membrane structure and functions. This concentration effect was time dependent with tetracaine. The quaternary amine methochlorpromazine acted as chlorpromazine only on open ghosts. On intact cells, it inhibited catecholamine receptors at higher concentration and monotonously decreased the order and microviscosity, as the anionic amphipath octanoic acid did. This is taken as evidence that the inner leaflet of the bilayer is the seat for the observed multiphasic changes of viscosity and the control of adenylate cyclase and catecholamine receptors. This could stem from either a preferential intercalation or a surface effect of the amphipaths in the inner leaflet of the membrane. Since the basal activity of adenylate cyclase was not affected in the presence of drugs, it may be inferred that the enzyme holds its activity but that its stimulation is modulated by the membrane physical state.

65 citations

Journal ArticleDOI
TL;DR: Intensities of peaks further upfield than this peak, previously attributed to deoxy-alpha subunits, are difficult to measure directly especially for samples containing inositol hexaphosphate, which appears to increase with temperature.

44 citations

Journal ArticleDOI
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