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Souto FT, de O Buske JL, Nicoleti CR, Dreyer JP, da S Heying R, Bortoluzzi AJ, Machado VG. Chromogenic chemodosimeter based on a silylated azo compound detects cyanide in water and cassava. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 260:119950. [PMID: 34038866 DOI: 10.1016/j.saa.2021.119950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 05/02/2021] [Accepted: 05/09/2021] [Indexed: 06/12/2023]
Abstract
A novel silylated azo compound was synthesized and fully characterized. This compound was used in a chromogenic chemodosimeter approach for the highly selective detection of cyanide (CN-) in acetonitrile/water and in an aqueous micellar system. The anion breaks the Si-O bond, delivering a dye and causing a change in the color of the solution (from yellow to blue). The chemodosimeter was employed for the naked-eye and quantitative detection of CN- in tap water and cassava roots.
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Affiliation(s)
- Francielly T Souto
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Jonatan L de O Buske
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Celso R Nicoleti
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Juliana P Dreyer
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Renata da S Heying
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Adailton J Bortoluzzi
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Vanderlei G Machado
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, CP 476, Florianópolis, Santa Catarina 88040-900, Brazil.
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Kunishima M, Kikuchi K, Kawai Y, Hioki K. Substrate-Selective Dehydrocondensation at the Interface of Micelles and Emulsions of Common Surfactants. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107706] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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3
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Kunishima M, Kikuchi K, Kawai Y, Hioki K. Substrate-selective dehydrocondensation at the interface of micelles and emulsions of common surfactants. Angew Chem Int Ed Engl 2012; 51:2080-3. [PMID: 22266803 DOI: 10.1002/anie.201107706] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Indexed: 11/05/2022]
Affiliation(s)
- Munetaka Kunishima
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa, Japan.
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Wu YW, Goody RS, Alexandrov K. Intein-mediated construction of a library of fluorescent Rab GTPase probes. Chembiochem 2011; 12:2813-21. [PMID: 22086656 DOI: 10.1002/cbic.201100377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Indexed: 11/08/2022]
Abstract
Rab GTPases play a key role in the regulation of membrane trafficking. Post-translational geranylgeranylation is critical for their biological activity and is conferred by Rab geranylgeranyl transferease (RabGGTase), together with an accessory factor, Rab escort protein (REP). Mechanistic studies of Rab prenylation and identification of RabGGTase inhibitors require sensitive reporters of Rab prenylation. In the present work, a combination of protein engineering and expressed protein ligation was used to construct a library of semisynthetic Rab7 fluorescent conjugates. In order to avoid synthesis of a large number of fluorescently labeled peptides, we developed a strategy that combined thiol-reactive dye-labeling of cysteine with in vitro protein ligation. Application of this strategy required optimization of labeling and ligation conditions to promote thiol labeling and disfavor intramolecular cyclization. Using this approach, we constructed 46 fluorescent sensors with different spectral properties that reported on the interaction of Rab7 with RabGGTase, REP-1, and the overall prenylation reaction. Two constructs, Rab7Δ3CCK(NBD) and Rab7Δ2SCCC-dans, displayed 2.5- and 1.5-fold increase in fluorescence, respectively, upon prenylation. Moreover, dansyl-, NBD (4-nitro-benzofurazan)-, I-BA-, and I-SO-labeled Rab7 conjugates exhibited two- to tenfold change in fluorescence upon binding to REP or RabGGTase. These fluorescent sensors allowed us to monitor Rab prenylation in real time and to investigate the assembly of Rab-REP binary and Rab-REP-RabGGTase ternary complexes.
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Affiliation(s)
- Yao-Wen Wu
- Department of Physical Biochemistry, Max-Planck Institute for Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
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Sinha A, Dutta RK, Bhat SN. Spectrophotometric and Thermodynamic Studies of Micellar Interaction of Surfactants with p-Nitrophenol. J DISPER SCI TECHNOL 2010. [DOI: 10.1080/01932690903269800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Chinelatto AM, Fonseca MTM, Kiyan NZ, Seoud OAE. Acid-Base Equilibria of Hydrophilic Indicators in Water-in-Oil Microemulsions. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19900940812] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Macka M, Borák J, Seménková L, Popl M, Mikeš V. Determination of Acyclovir in Blood Serum and Plasma by Micellar Liquid Chromatography with Fluorimetric Detection. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10826079308020992] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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López-Fontán JL, González-Pérez A, Costa J, Ruso JM, Prieto G, Schulz PC, Sarmiento F. The critical micelle concentration of tetraethylammonium perfluorooctylsulfonate in water. J Colloid Interface Sci 2006; 294:458-65. [PMID: 16139286 DOI: 10.1016/j.jcis.2005.07.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 07/14/2005] [Accepted: 07/19/2005] [Indexed: 11/28/2022]
Abstract
The aggregation characteristics of tetraethylammonium perfluorooctylsulfonate in water were studied by several techniques: conductivity, pH, ion-selective electrodes, and surface tension. It was concluded that the aggregation process is gradual and starts with the formation of oligomers such as ion pairs that grow to give spherical micelles, which become wormlike with increasing concentration. Because of the size and hydrophobicity of the counterion, micelles quickly increase in ionization degree up to about 0.5. Differences among different critical micelle concentration values in the literature are explained on the basis of the gradual formation of micelles.
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Affiliation(s)
- José L López-Fontán
- Grupo de Biofísica e Interfases, Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Neumann MG, Pastre IA, Chinelatto AM, El Seoud OA. Effects of the structure of anionic polyelectrolytes on surface potentials of their aggregates in water. Colloid Polym Sci 1996. [DOI: 10.1007/bf00652471] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Gitler C, Zarmi B, Kalef E. Use of cationic detergents to enhance reactivity of protein sulfhydryls. Methods Enzymol 1995; 251:366-75. [PMID: 7651218 DOI: 10.1016/0076-6879(95)51140-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- C Gitler
- Department of Membrane Research and Biophysics, Weizmann Institute of Science, Rehovot, Israel
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Kraayenhof R, Sterk GJ, Sang HW. Probing biomembrane interfacial potential and pH profiles with a new type of float-like fluorophores positioned at varying distance from the membrane surface. Biochemistry 1993; 32:10057-66. [PMID: 8399132 DOI: 10.1021/bi00089a022] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Fluorophores of a new type were synthesized to probe the electrostatic potential or pH profiles in the external interface of biomembranes. The probes consist of the pH-sensitive fluorophore 7-hydroxycoumarin, coupled to a tetradecyl (myristyl) tail by a spacer group of varying length. A positively charged group is included between the tetradecyl and spacer groups to encourage a float-like alignment in the membrane head-group region. Three probes of this type were compared with 4-heptadecyl-7-hydroxycoumarin the fluorophore of which is embedded in the lipid head-group domain. Thus, a ruler-type positioning of the fluorophores was obtained at about 0.2, 0.6, 1.0, and 1.3 nm from the surface. The membrane-bound probes were tested in well-defined liposomes prepared by extrusion with different surface charge densities and size. The predicted positioning of the float-like probes is supported by their binding behavior in liposomes and by steady-state and nanosecond time-resolved fluorescence anisotropy, as well as by their accessibility to different quenchers. The interfacial electrostatic potential (psi d) and pH (pHd) values were derived from the observed apparent pKa shifts of the probes. The obtained psi d and pHd profiles as function of the surface potential (psi 0) and distance from the membrane surface are in good harmony with predictions from nonlinear Gouy-Chapman theory. The electrokinetic potentials (zeta) of the liposome series, measured by Doppler-electrophoretic frequency shift of laser light scattering, are in good proportion to the probe data. When bound to yeast cells, these probes monitor interfacial changes in parallel with glucose-induced medium acidification.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Kraayenhof
- Department of Molecular and Cellular Biology, Vrije Universiteit Amsterdam, The Netherlands
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14
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Chinelatto AM, Okano LT, El Seoud OA. Effect of anionic and nonionic water-in-oil microemulsions on acid-base equilibria of hydrophilic indicators. Colloid Polym Sci 1991. [DOI: 10.1007/bf00665500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Effect of a positively charged water-in-oil microemulsion on the apparent pKa of a hydrophilic indicator. J Colloid Interface Sci 1991. [DOI: 10.1016/0021-9797(91)90325-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Fromherz P. Lipid coumarin dye as a probe of interfacial electrical potential in biomembranes. Methods Enzymol 1989; 171:376-87. [PMID: 2593847 DOI: 10.1016/s0076-6879(89)71021-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Drummond CJ, Grieser F. ABSORPTION SPECTRA AND ACID-BASE DISSOCIATION OF THE 4-ALKYL DERIVATIVES OF 7-HYDROXYCOUMARIN IN SELF-ASSEMBLED SURFACTANT SOLUTION: COMMENTS ON THEIR USE AS ELECTROSTATIC SURFACE POTENTIAL PROBES. Photochem Photobiol 1987. [DOI: 10.1111/j.1751-1097.1987.tb08401.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Drummond CJ, Grieser F. The ionization behaviour of DL-alpha-tocopherol (vitamin E) in model membranes: micelles and vesicles. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 836:275-8. [PMID: 4027265 DOI: 10.1016/0005-2760(85)90076-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ionization behaviour of DL-alpha-tocopherol (vitamin E) has been investigated in dodecyltrimethylammonium bromide (DTAB), hexadecyltrimethylammonium chloride (CTAC) and dodecyldimethyl propiobetaine (DPB) micelles and didodecyldimethylammonium bromide (DDAB) and dimyristoylphosphatidylcholine (DMPC) vesicles. The pKa values for DL-alpha-tocopherol in the aqueous self-assembled solutions of DTAB, CTAC, DPB, DDAB and DMPC were 12.0 +/- 0.1, 11.7 +/- 0.1, 13.1 +/- 0.1, 11.0 +/- 0.2 and greater than 14.5, respectively. It is shown how these pKa results confirm that DL-alpha-tocopherol exists predominantly in the un-ionized form when localized in any type of micelle or vesicle at physiological pH values.
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Vidal M, Bienvenue A, Sainte-Marie J, Philippot J. The influence of the internal content of negatively charged liposomes on their interaction with high-density lipoprotein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1984; 138:399-405. [PMID: 6697995 DOI: 10.1111/j.1432-1033.1984.tb07929.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The release of the internal content of negatively charged phosphatidylcholine/phosphatidylserine vesicles under the influence of high density lipoprotein was studied. Under standard conditions (the same composition outside and inside the compartment) the leakage of negative liposomes increased significantly. However, a high internal concentration of calcein provoked a sealing effect, exhibited both in sucrose and in calcein release. This sealing effect is not related to the size of vesicles, the fluidity of the membrane, the distribution of phosphatidylserine molecules, or the membrane potential. Our data indicate that surface potential influences this effect, probably in addition to a lateral pressure effect such as with cholesterol. The surface potential, as measured by the water-lipid partition coefficient of fatty acids, is strongly affected by internal ionic strength when liposomes contain calcein as well as other polyanions (6-carboxyfluorescein, sodium citrate).
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García-Soto J, Fernández MS. The effect of neutral and charged micelles on the acid-base dissociation of the local anesthetic tetracaine. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 731:275-81. [PMID: 6849924 DOI: 10.1016/0005-2736(83)90019-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The influence of surfactant micelles on the acid-base dissociation of the charged tertiary amino group of the local anesthetic, tetracaine, has been investigated. From measurements of tetracaine fluorescence as a function of bulk pH, apparent pK values of 6.88, 7.58 and 9.92 were found in the presence of cationic, neutral and anionic micelles, respectively, in 10 mM NaCl. These values are considerably displaced with respect to the pK in aqueous solution which is 8.26. Such large shifts can be attributed to the effect of the surface polarity and electrical potential on the dissociation behavior of the anesthetic bound to micelles. It can be expected that the acid-base dissociation of a local anesthetic adsorbed to nerve fibers will also be affected by the properties of the membrane surface. Thus, it is suggested that the influence of the interfacial region on the pK of surface-bound molecules should not be disregarded when estimating the proportion of charged and uncharged forms of local anesthetics interacting with axonal membranes.
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23
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Harris CM, Selinger BK. Excited-State Processes of Naphthols in Aqueous Surfactant Solution. ACTA ACUST UNITED AC 1983. [DOI: 10.1524/zpch.1983.134.1.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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24
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Terada H. The interaction of highly active uncouplers with mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 639:225-42. [PMID: 7039674 DOI: 10.1016/0304-4173(81)90011-2] [Citation(s) in RCA: 239] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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26
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Abstract
The ability of the fluorescent pH indicator 4-heptadecylumbelliferone to detect the electrical potential at the surface of negatively charged liposomes, was investigated. The vesicles were prepared from mixtures of egg lecithin and dicetyl phosphate at different molar ratios in NaCl solutions of various concentrations. It has been found that the dependence of the experimental surface potential in the proportion of charged lipid in the vesicles and on the salt concentration in the aqueous phase, was very similar to the predictions of the Gouy-Chapman equation as calculated by assuming a reasonable value for the mean molecular area of the lamellar lipids. In view of the good correlation obtained between the experimental and theoretical results, it is concluded that 43-heptadecylumbelliferone is quantitatively sensitive to changes in double-layer potential at the surface of lipid vesicles.
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Gutman M, Huppert D, Pines E, Nachliel E. Probing the micelle/water interface by a rapid laser-induced proton pulse. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 642:15-26. [PMID: 7225376 DOI: 10.1016/0005-2736(81)90133-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The laser-induced pH jump (Gutman, M. and Huppert, D.J. (1979) Biochem. Biophys. Methods 1, 9-19) has a time resolution capable of measuring the diffusion-controlled rate constant of proton binding. In the present study we employed this technique for measuring the kinetics of protonation-deprotonation of surface groups of macromolecules. The heterogeneous surface of proteins excludes them from serving as a simple model, therefore we used micelles of a neutral detergent (Brij 58) as a high molecular weight structure. The charge was varied by the addition of a low concentration of sodium dodecyl sulfate and the surface group with which the protons react was an adsorbed pH indicator (bromocresol green or neutral red). The dissociation of a proton from adsorbed bromocresol green is slower than that from free indicator. This effect is attributed to the enhanced stabilization of the acid form of the indicator in the pallisade region of the micelle. The pK shift of bromocresol green adsorbed on neutral micelles is thus quantitatively accounted for by the decreased rate of proton dissociation. Indicators such as neutral red, which are more lipid soluble in their alkaline form, do not exhibit such decelerated proton dissociation in their adsorbed state nor a pK shift on adsorption to neutral micelles. The protonation of an indicator is a diffusion-controlled reaction, whether it is free in solution or adsorbed on micelles. By varying the electric charge of the micelle this rate can be accelerated or decelerated depending on the total charge of the micelle. The micellar charge calculated from this method was corroborated by other measurements which rely only on equilibrium parameters. The high time resolution of the pH jump is exemplified by the ability to estimate the diffusion coefficient of protons through the hydrated shell of the micelle.
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Higuti T, Arakaki N, Niimi S, Nakasima S, Saito R, Tani I, Ota F. Anisotropic inhibition of energy transduction in oxidative phosphorylation in rat liver mitochondria by tetraphenylarsonium. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)43876-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Schapendonk AH, Hemrika-Wagner AM, Theuvenet AP, Sang HW, Vredenberg WJ, Kraayenhof R. Energy-dependent changes of the electrokinetic properties of chloroplasts. Biochemistry 1980; 19:1922-7. [PMID: 7378383 DOI: 10.1021/bi00550a030] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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30
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Pfaff E, Schuler B, Krell H, Höke H. Viability control and special properties of isolated rat hepatocytes. Arch Toxicol 1980; 44:3-21. [PMID: 6992743 DOI: 10.1007/bf00303179] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The need for quick viability tests is stressed. Aas these should achieve more than statically categorizing dead or non-dead cells, several procedures are suggested that picture the energetic state of the cells. The almost classical criterion of this category, namely stimulation of respiration by succinate, must be questioned on the basis of the present results. It is shown, that restricted respiration by succinate is not due to limited permeability of the plasma membrane, but to competition by endogenous substrates for uptake into mitochondria. Distribution equilibria for succinate appear to be according to (delta pH)2 with regard to cytoplasm. They are attained within 5-20 s or faster. Uptake is in part regulated by the surface charge density. Permeability changes caused by effectors of surface charge, such as amphiphilic ions, are examplified for succinate, chloride, phosphate, Na+, K+, and Ca2+. Such changes repeatedly also occur after pulses of BSP. They are counterregulated by the cell within a minute in a manner dependent on BSP concentration and the state of the cells. During the preincubation phase, that is the time of readaptation after transfer of cells from 0 degree C to higher temperature, a special labile state transiently occurs, where cyclic permeability changes for Ca2+, Na+, K+ can be caused by substrate addition, especially succinate, and/or ATP. The extent of these changes and their sequence again depend on the energetic state of the cells. In a probably narrow energetic window a sequence of cation movements reminding of that after depolarization of an excitable cell, is observed. Manipulation of the Na+/K+-ratio by variation of preincubation time and by ouabain shows that this is not simply the denominator for reversible calcium uptake. As the surface charge appears to reflect the energetic state, ANS fluorescence is applied to monitor the state of the plasma membrane, though difficulties arising from a slow ANS permeation are not yet solved.
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32
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Kell DB. On the functional proton current pathway of electron transport phosphorylation. An electrodic view. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 549:55-99. [PMID: 38839 DOI: 10.1016/0304-4173(79)90018-1] [Citation(s) in RCA: 242] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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33
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Fujii H, Kawai T, Nishikawa H. Determination of pH in Reversed Micelles. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1979. [DOI: 10.1246/bcsj.52.2051] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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34
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Walz D. Thermodynamics of oxidation-reduction reactions and its application to bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 505:279-353. [PMID: 219888 DOI: 10.1016/0304-4173(79)90007-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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35
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Mehlhorn RJ, Packer L. Membrane surface potential measurements with amphiphilic spin labels. Methods Enzymol 1979; 56:515-26. [PMID: 223008 DOI: 10.1016/0076-6879(79)56049-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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Ohki S, Sauve R. Surface potential of phosphatidylserine monolayers. I. Divalent ion binding effect. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 511:377-87. [PMID: 687618 DOI: 10.1016/0005-2736(78)90274-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Surface potentials of phosphatidylserine monolayers have been measured in the presence of different divalent ion concentrations in order to determine the way in which divalent ions bind to the membrane surface. The association constants for divalent ions (Mg2+, Ca2+ and Mn2+) with the phosphatidylserine membrane have been obtained from the experimental data and simple ion binding theory. The order of divalent ion binding to the membrane is Mn2+ greater than Ca2+ greater than Mg2+. However, none of the divalent ions used completely neutralized the negative charge of phosphatidylserine even at relatively high concentrations. The amounts of the divalent ions bound depended upon the concentration of the monovalent ions present in the subphase. It is suggested that the amounts of bound ions obtained from the use of radioisotope tracer methods may include a considerable contribution from the excess free ions in the double layer region of the phosphatidylserine membrane.
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Kano K, Fendler JH. Pyranine as a sensitive pH probe for liposome interiors and surfaces. pH gradients across phospholipid vesicles. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 509:289-99. [PMID: 26400 DOI: 10.1016/0005-2736(78)90048-2] [Citation(s) in RCA: 274] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pyranine is shown to be a convenient and sensitive probe for reporting pH values, pHi, at the interior of anionic and at the outer surface of cationic liposomes. It is well shielded from the phospholipid headgroups by water molecules in the interior of anionic liposomes, but it is bound to the surface of cationic liposomes. Hydrogen ion concentrations outside the liposomes, 'bulk pH values', pHo, were measured by a combination electrode. While pHi = pHo for neutral, pHi less than pHo for anionic and pHi greater than pHo for cationic liposomes prepared in 5.0 . 10(-3) M phosphate buffers. pKa values for the ionization of pyranine were 7.22 +/- 0.04 and 6.00 +/- 0.05 in water and at the external surface of cationic liposomes. The surface potential for cationic liposomes containing dipalmitoyl-DL-alpha-phosphatidylcholine, cholesterol and octadecylamine in the molar ratio of 1.00 : 0.634 : 1.01, were calcuated to be +72.2 mV. Proton permeabilities were measured for single and multicompartment anionic liposomes. Transfer of anionic liposomes prepared at a given pH to a solution of different pH resulted in a pH gradient if sodium phosphate or borate were used as buffers. In the presence of sodium acetate proton equilibration is promptly established.
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Vaz WL, Nisksch A, Jähnig F. Electrostatic interactions at charged lipid membranes. Measurement of surface pH with fluorescent lipoid pH indicators. EUROPEAN JOURNAL OF BIOCHEMISTRY 1978; 83:299-305. [PMID: 23947 DOI: 10.1111/j.1432-1033.1978.tb12094.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The 5-dimethylaminonapthalene-1-sulfonyl (dansyl) chromophore attached to the polar head groups of lipids has been used as a fluorescent lipoid pH indicator to evaluate the interfacial pH in lipid-water lamellar systems prepared from negatively charged lipids. The pH in the vicinity of the charged lipid bilayers is different from the pH of the bulk aqueous phase and the difference is a function of the electrolyte concentration in the aqueous phase and of the lipid packing in the bilayer. At a fixed electrolyte concentration in the aqueous phase, the observed interfacial pH is 0.6 to 0.7 pH units lower above the thermal phase transition of the lipid than it is below this temperature. A quantitative interpretation of the results is given on the basis of the Gouy-Chapman theory. The results indicate that the dansyl chromophore is located in front of the charged surface and its distance from this surface increases with a decrease in lipid packing.
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Electrostatic Potentials at Membrane-Solution Interfaces. CURRENT TOPICS IN MEMBRANES AND TRANSPORT 1977. [DOI: 10.1016/s0070-2161(08)60677-2] [Citation(s) in RCA: 598] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Pick U, Avron M. A method for measuring the internal pH in illuminated chloroplasts based on the stimulation of proton uptake by amines. EUROPEAN JOURNAL OF BIOCHEMISTRY 1976; 70:569-76. [PMID: 12954 DOI: 10.1111/j.1432-1033.1976.tb11048.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A simple method for measuring the internal pH of chloroplasts during steady-state illuminations based on the stimulation of proton uptake by monofunctional amines was developed. Predictions of a mathematical derivation concerning the dependence of the stimulation on the amine concentration, the internal volume, the pK of the amine and the external pH have been verified experimentally. To circumvent uncoupling and swelling due to large internal accumulation of amines extrapolation of the stimulation to low amine concentrations was suggested and shown to lead to valid values. Alternatively, swelling could be largely reduced in a medium containing potassium aspartate and valinomycin.
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Castle JD, Hubbell WL. Estimation of membrane surface potential and charge density from the phase equilibrium of a paramagnetic amphiphile. Biochemistry 1976; 15:4818-31. [PMID: 186095 DOI: 10.1021/bi00667a011] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The distribution of a paramagnetic amphiphile, N,N-dimethyl-N-nonyl-N-tempoylammonium ion, between the membranes of charged phospholipid vesicles and the surrounding aqueous medium was studied by electron paramagnetic resonance spectroscopy. By systematically varying the surface charge of the vesicles and the aqueous electrolyte concentration, the distribution was shown to indicate vesicle surface potential. At each fixed phospholipid composition, the surface potential exhibited a dependence on aqueous NaCl concentration very similar to that predicted by the Gouy equation. The ability to sense and quantitate surface potentials makes this facile and sensitive technique of value in the study of cell and organelle surfaces.
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Schäfer G. Some new aspects on the interaction of hypoglycemia-producing biguanides with biological membranes. Biochem Pharmacol 1976; 25:2015-24. [PMID: 985539 DOI: 10.1016/0006-2952(76)90424-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Schäfer G, Rowohl-Quisthoudt G. Influence of surface potentials on the mitochondrial H+ pump and on lipid-phase transitions. J Bioenerg Biomembr 1976; 8:73-81. [PMID: 8445 DOI: 10.1007/bf01558629] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It has been shown that the surface potential of lipid membranes, as well as of mitochondria, can be shifted more positive by absorption of alkylbiguanides. Both phospholipid vesicles and natural membranes respond in an analogous way to this shift. Ion activities at the immediate membrane surface are influenced by sign and magnitude of the surface charge. Corresponding effects on ion transport and on fluorescence-probe binding can be observed. The mitochondrial H+ pump is inhibited when the surface charge is shifted more positive. In contrast,the absolute charge density determines the temperature of the ordered-fluid transition. The latter is increased by biguanides, suggesting that the membrane is rendered more rigid. The experiments make obvious that physical relations derived from model systems apply equally well to lipid-containing natural membranes.
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Schäfer G, Rowohl-Quisthoudt G. Influence of electrostatic surface potential on mitochondrial ADP-phosphorylation. FEBS Lett 1975; 59:48-51. [PMID: 1225620 DOI: 10.1016/0014-5793(75)80338-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Reed KC, Bygrave FL. A kinetic study of mitochondrial calcium transport. EUROPEAN JOURNAL OF BIOCHEMISTRY 1975; 55:497-504. [PMID: 240699 DOI: 10.1111/j.1432-1033.1975.tb02187.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This report describes a kinetic analysis of energy-linked Ca2+ transport in rat liver mitochondria, in which a ruthenium red/EGTA [ethanedioxy-bis(ethylamine)-tetraacetic acid] quenching technique has been used to measure rates of 45Ca2+ transport. Accurately known concentrations of free 45Ca2+ were generated with Ca2+/nitrilotriacetic acids buffers for the determination of substrate/velocity relationships. The results show that the initial velocity of transport is a sigmoidal function of Ca2+ concentration (Hill coefficient = 1.7), the Km being 4 muM Ca4 at 0 degrees C and pH 7.4. These values for the Hill coefficient and the Km remain constant in the presence of up to 2 mM phosphate, but with 10 mM acetate both parameters are increased slightly. Both permeant acids increase the maximum velocity to an extent dependent on their concentration. The Ca2+-binding site(s) of the carrier contains a group ionizing at pH approximately 7.5 at 0 degrees C, which is functional in the dissociated state. The stimulatory effect of permeant acids is ascribed to their facilitating the release of Ca2+ from the carrier to the internal phase, an interpretation which is strengthened by the lack of effect of the permeant anion SCN- on Ca2+ transport. Studies on the time-course of Ca2+ uptake and of EFTA-induced Ca2+ efflux from pre-loaded mitochondria demonstrate the reversibility of the carrier in respiring mitochondria and the extent to which this property is influenced by permeant acids. These data are accommodated in a carrier mechanism based on electrophoretic transport of Ca2+ bound to pairs of interacting acidic sites.
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Bakker EP, Arents JC, Hoebe JP, Terada H. Surface potential and the interaction of weakly acidic uncouplers of oxidative phosphorylation with liposomes and mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 387:491-506. [PMID: 237541 DOI: 10.1016/0005-2728(75)90088-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The pH dependence of the binding of weakly acidic uncouplers of oxidative phosphorylation to rat-liver mitochondria and liposomes is mainly determined by the pKa of the uncoupler molecule. The absorption and fluorescene excitation spectra of the anionic form of weakly acidic uncouplers of oxidative phosphorylation are red-shifted upon interaction with liposomal or mitochondrial membranes. The affinity for the liposomes, as deduced from the red shift, is independent of the degree of saturation of the fatty acid chains of different lecithins. The intensity of the spectra at one pH value is strongly dependent upon the surface charge of the liposomes. With positively charged liposomes the results obtained can be almost quantitatively explained with the Gouy-Chapman theory, but with negatively charged ones deviations are observed. At a particular pH, the divalent ion Ca-2+ stongly influences the intensity of the spectra in the presence of negatively charged liposomes, but has no effect with neutral liposomes. With mitochondrial membranes an effect of Ca-2+ similar to that with negatively charged liposomes is observed. Depletion of the phospholipids of the mitochondria and subsequent restoration of the mitochrondrial membrane with lecithin, strongly diminishes this effect, but restoration with negatively charged phospholipids does not influence it. From these observations it is concluded that the anionic form of the uncoupler molecule when bound to mitochondria is located within the partly negatively charged phospholiped moiety of the membrane, with its anionic group pointing to the aqueous solution.
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Terada H. Some biochemical and physiochemical properties of the potent uncoupler SF 6847 (3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile). BIOCHIMICA ET BIOPHYSICA ACTA 1975; 387:519-32. [PMID: 237542 DOI: 10.1016/0005-2728(75)90090-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Various physicochemical and biochemical properties of the most potent uncoupler of oxidative phosphorylation known to date 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847), such as pH dependence of the uncoupling activity and binding to mitochondria, spectral properties in the presence of different types of liposomes, biopolymers and mitochondria, and effects on model membrane systems have been investigated. From the results, it is concluded that the uncoupler most likely is localized in the phospholipid part of the membrane.
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Abstract
Fluorescence has been used in biochemical studies for many years but only recently has the information content and the practical applicability of the fluorescence method been fully realized.Following the early studies of Newton (1954) and Weber (11954) and after the initial utilization of fluorescent probes by Chance and coworkers (Azziet al.1969) and Tasakiet al.(1968), in the study of membranes, the use of fluorescence to provide structural information at microscopic or molecular levels in biological membranes has become widespread. widespread. The application of the fluorescence technique to biological systems has progressed parallel to the development of a theoretical basis for fluorescence data interpretation and the synthesis of a large number of fluorescent probes, organic molecules having fluorescence characteristics that are dependent on their environment.
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H+ Ion Transport and Energy Transduction in Chloroplasts. ACTA ACUST UNITED AC 1975. [DOI: 10.1016/s0070-2161(08)60858-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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