Relations Between the Constants of Dibasic Acids and of Amphoteric Electorolytes

Adms, Elliot Quincy

doi:10.1021/ja02265a008

Cited by 116 publications

(54 citation statements)

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“…It has been shown elsewhere 43 that the difference between pK a1 and pK a2 of a diprotic ligand can be used as a measure of the average separation between protonation sites. Applied to the current situation, the difference in pK a values is slightly lower for H 2 2 at 1.13 compared to H 2 1 at 1.60 as shown in Table 4.…”

Section: Solution Thermodynamicsmentioning

confidence: 99%

Highly Luminescent Lanthanide Complexes of 1-Hydroxy-2-pyridinones

et al. 2008

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The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III) and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission ( Eu tot Φ ~ 21.5 %,) with high stability (pEu ~ 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure, and were found to agree with corresponding TD-DFT calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.

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Section: Solution Thermodynamicsmentioning

confidence: 99%

Highly Luminescent Lanthanide Complexes of 1-Hydroxy-2-pyridinones

et al. 2008

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“…However, it is not likely that such value will lead to accurate predictions of peptide charges at pH values very different from the ZP, where the charge is larger than unity, for two reasons. First, assigning equal pK, values to the same type of groups (terminal COOH and NH,, side-chain groups of the same type) and considering these as pK, values of the entire molecule neglects the statistical effect that occurs when more than one protolytic group is present [22]. This occurs independent of any (additional) electrostatic or conformational effect of one group on the other, as will be considered later.…”

Section: Prediction Of Pk Values Of Peptidesmentioning

confidence: 99%

Simulation and optimization of peptide separation by capillary electrophoresis

Cifuentes

Poppe

1994

Journal of Chromatography A

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Simulation and optimization of peptide separation by capillary electrophoresis.Cifuentes, A.; Poppe, H. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractThe different mobility equations that have appeared in the literature for predicting peptide mobility were compared. A modified equation that relates the mobility of individual proteolytic species of a peptide to its composition has been obtained: Jo = 1758 log(1 + 0.297q)lM0.41', where p is the electrophoretic mobility in 10e9 m'ls -V, q is the integral value of the charge of the species and M its molecular mass. Also, a rough estimation of the set of pK, values for a peptide was developed. The usefulness of this equation together with a computer program for predicting separations of compounds by capillary zone electrophoresis is demonstrated, employing real electropherograms of peptides from the literature or from experiments.

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“…The relation between the stoichiometric ( K , and K,) and intrinsic ( K I , K;', F1,2 and two-site system is given by the following equations [26]: The other case that allows determination of the intrinsic dissociation constants is that in which the sites are initially identical and the second molecule binds with negative or positive co-operativity, so that K i = K;' and = K'l,z. By using Eqns (3) and (4), it follows that K 1 = 0.5 K i and K2 = 2 P1,2.…”

Section: Scheme 1 Intrinsic Dissociation Constants Jor the Binding mentioning

confidence: 99%

Properties of the MgATP and MgADP binding sites on the Fe protein of nitrogenase from Azotobacter vinelandii

Cordewener¹,

Haaker²,

Ewijk³

et al. 1985

Eur J Biochem

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Flow dialysis was used to study the binding of MgATP and MgADP to the nitrogenase proteins of Azotobucter vinelundii. Both reduced and oxidized Av, bind two molecules of MgADP, with the following dissociation constants: reduced Av,, K1 = 0.091 k 0.021 mM and K2 = 0.044 * 0.009 mM; oxidized Av,, K1 = 0.024 k 0.015 mM and K 2 = 0.039 * 0.022 mM. Binding of MgADP to reduced Av, shows positive co-operativity.Oxidized Av, binds two molecules of MgATP with dissociation constants K1 = 0.049 k 0.016 mM and K 2 = 0.18 k 0.05 mM. Binding data of MgATP to reduced Av2 can be fitted by assuming one binding site, but a better fit was obtained by assuming two binding sites on the protein with negative co-operativity and with dissociation constants K , = 0.22 & 0.03 mM and K2 = 1.71 f 0.50 mM.It was found that results concerning the number of binding sites and the dissociation constants of MgATPAv2 and MgADP-Av2 complexes depend to a great extent on the specific activity of the Av2 preparation used, and that it is difficult to correct binding data for inactive protein.

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Relations Between the Constants of Dibasic Acids and of Amphoteric Electorolytes

Cited by 116 publications

References 0 publications

Highly Luminescent Lanthanide Complexes of 1-Hydroxy-2-pyridinones

Highly Luminescent Lanthanide Complexes of 1-Hydroxy-2-pyridinones

Simulation and optimization of peptide separation by capillary electrophoresis

Properties of the MgATP and MgADP binding sites on the Fe protein of nitrogenase from Azotobacter vinelandii

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