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: The results indicate that CT DNA can assemble on the surface of UCPs mainly by relative stronger hydrophobic force and electrostatic binding, and the predominant interaction site is the deoxyribosyl phosphate backbone of CT DNA.
5 citations
TL;DR: It is explained that Rg1 and Rb1 inhibited amyloid fibril formation by κ-casein because the molecular spatial conformation and physical property of λ- casein changed causing by the complex formation between GS and κ -casein.
Abstract: The interaction of the ginsenosides (GS) including ginsenoside Rg1, Rb1 and Re with κ-casein and the effects of GS inhibiting amyloid fibril formation by κ-casein have been investigated in vitro by fluorescence and ultraviolet spectra. Results showed that Rg1 and Rb1 had dose-dependent inhibitory effects on reduced and carboxymethylated κ-casein (RCMκ-CN) fibril formation, while Re resulted in an increase in the rate of fibril formation. The enhancement in RLS intensity was attributed to the formation of new complex between GS and RCMκ-CN, and the corresponding thermodynamic parameters (ΔH, ΔS and ΔG) were assayed. The steady-state ultraviolet-visible absorption spectra had also been tested to observe if the ground-state complex formed, and it showed the same result as RLS spectra. The binding constants and the number of binding sites between GS and RCMκ-CN at different temperatures had been evaluated from relevant fluorescence data. According to the Forster non-radiation energy transfer theory, the binding distance between RCMκ-CN and GS was calculated. The fluorescence lifetime of RCMκ-CN was longer in the presence of GS than in absence of GS, which was evident that the hydrophobic interaction plays a major role in the binding of GS to RCMκ-CN. From the results of synchronous fluorescence, it could be deduced that the polarity around RCMκ-CN Trp97 residue decreased and the hydrophobicity increased after addition of Rg1 or Rb1. Based on all the above results, it is explained that Rg1 and Rb1 inhibited amyloid fibril formation by κ-casein because the molecular spatial conformation and physical property of κ-casein changed causing by the complex formation between GS and κ-casein.
5 citations
TL;DR: Both the results of the multispectral method and molecular docking showed that SBAL could bind HSA with van der Waals force and hydrogen bonds.
Abstract: Salbutamol (SBAL), a kind of short-acting beta 2-adrenergic agonist, has been mainly used to treat bronchial asthma and other allergic airway diseases clinically. In this study, the interaction mechanism between salbutamol and human serum albumin was researched by the multispectral method and molecular docking. The fluorescence intensity of HSA could be regularly enhanced with the increase of SBAL concentration. Both the results of the multispectral method and molecular docking showed that SBAL could bind HSA with van der Waals force and hydrogen bonds. The binding mechanism was further analysed by UV-Vis and synchronous fluorescence spectra. The contents of the secondary structure of free HSA and SBAL-HSA complex were evaluated using CD spectra.
5 citations
Cites methods from "Interaction of chlorpromazine with ..."
...To further illuminate the interaction mechanism of SBAL-HSA, the Bhattacharya equation (equation (1)) [19, 22] was used to process the fluorescence intensity value (λex\λem, 295\344 nm) at three temperatures 288, 300, and 310K:...
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...0e optimal geometry conformation of SBAL was done by the distance-dependent dielectric function in the standard Tripos force field [18, 19] with the energy gradient of 0....
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TL;DR: It is proved that the microenvironments where Trp and Tyr residues of the enzyme exist have obviously changed after treatment by boric acid, which indicates that the established model of inhibition kinetics is suitable.
Abstract: Inhibitory kinetics of jack bean urease by boric acid has been studied in this paper. According to the kinetic parameters for the enzyme obtained from Lineweaver–Burk plot, it is shown that the Km is equal to 5.11 ± 0.22 mM and Vm is equal to 1.04 ± 0.04 mM min−1. Besides, the inhibition of urease by boric acid at lower than 0.25 mM is a reversible reaction with residual activity and the inhibition belongs to be competitive. Additionally, it is found that the inhibition is maximal on the condition that pH value is between 7.0 and 9.0 at 30 °C. Furthermore, the microscopic rate constants were determined. The values of k+0 equal 0.026 × 10−3, 0.026 × 10−3, 0.027 × 10−3 μM−1 min−1, while the k−0 equal 0.031 × 10−3, 0.032 × 10−3 S−1, which indicates that the established model of inhibition kinetics is suitable. It is turned out that one molecule of boric acid binds to the active unit of the enzyme, which makes the enzyme lose its activity. In accordance with experimental results of the fluorescence spectrum at different boric acid concentrations, it is proved that the microenvironments where Trp and Tyr residues of the enzyme exist have obviously changed after treatment by boric acid.
5 citations
TL;DR: Glycyrrhizin inhibits ferryl-haemoglobin formation, peroxidase and esteraselike activities of the heme protein, and reduces haemoglobin-mediated oxidative damage without affecting oxygen-binding capacity of the protein.
Abstract: This study investigates interaction of glycyrrhizin (an herbal therapeutic agent) with human haemoglobin. The interaction is confirmed by glycyrrhizin-induced quenching of absorbance and fluorescence data. Both hydrophobic and electrostatic interactions appear to be involved in glycyrrhizin-haemoglobin binding. The binding causes no change in the secondary structure of haemoglobin. The interaction decreases H 2 O 2 - induced iron release from haemoglobin and haemoglobin- mediated oxidative reactions. Glycyrrhizin inhibits ferryl-haemoglobin formation, peroxidase and esteraselike activities of the heme protein. Almost no oxygen is released from haemoglobin due to glycyrrhizin binding. The interaction thus reduces haemoglobin-mediated oxidative damage without affecting oxygen-binding capacity of the protein, and may be an advantage in therapeutic application of glycyrrhizin.
5 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