Potentiometrische Untersuchung der Bildungsgleichgewichte von bin�ren und tern�ren Komplexen von Kobalt(II) mit Adenosin-5?-mono-, -di- und -triphosphat und einigen biologisch bedeutenden polybasischen Sauerstoffs�uren

Azab, Hassan A.; El-Nady, A. M.; Hassan, Ahmed I.; Azkal, R. S. A.

doi:10.1007/bf00811513

Cited by 11 publications

(9 citation statements)

References 32 publications

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“…Formation constants for the normal ternary complexes and protonation constants for primary and secondary ligands were refined with the SUPERQUAD computer program (Gans et al, 1985). The same computer program has been used by the author in previous publications (Azab et al, 1993(Azab et al, , 1994(Azab et al, , 1995. The constants were refined by minimizing U, defined by where E obs and E calc refer to the measured potential and that calculated from eq 1.…”

Section: Resultsmentioning

confidence: 99%

Ternary Complexes in Solution. Comparison of the Coordination Tendency of Some Biologically Important Zwitterionic Buffers toward the Binary Complexes of Some Transition Metal Ions and Some Amino Acids

Anwar

Azab

1999

J. Chem. Eng. Data

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Potentiometric equilibrium measurements have been performed at (25.0 ± 0.1) °C and ionic strength I = 0.1 mol dm-3 (KNO3) for the interaction of glycine (aminoethanoic acid), serine (2-amino-3-hydroxypropanoic acid), methionine (2-amino-4-(methylthio)butanoic acid), aspartic acid (aminobutanedioic acid), glutamic acid (2-aminopropanedioic acid), and histidine (α-amino-1H-imidazole-4-propanoic acid) and Cu(II), Co(II), Ni(II), Mn(II), and Zn(II) with the biologically important secondary ligand zwitterionic buffers β-hydroxy-4-morpholinepropanesulfonic acid (MOPSO), 4-morpholinepropanesulfonic acid (MOPS), 3-[bis(2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid (DIPSO), and 3-[N-tris(hydroxymethyl)methyl)amino]-2-hydroxypropanesulfonic acid (TAPSO) in 1:1:1 and 1:1:2 ratios, and the formation of various 1:1:1 ternary complexes and 1:1:2 quaternary complex species was inferred from the potentiometric pH titration curves. Initial estimates of the formation constants of the resulting species and the acid dissociation constants of the different amino acids and secondary ligands studied have been refined with the SUPERQUAD computer program. The order of stability of the different normal ternary complexes in the systems under investigation in terms of metal ion follows generally the trend Cu(II) > Ni(II) > Co(II) > Zn(II) > Mn(II).

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Section: Resultsmentioning

confidence: 99%

Ternary Complexes in Solution. Comparison of the Coordination Tendency of Some Biologically Important Zwitterionic Buffers toward the Binary Complexes of Some Transition Metal Ions and Some Amino Acids

Anwar

Azab

1999

J. Chem. Eng. Data

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“…Ternary complexes of trivalent lanthanides with ATP and EDTA have been investigated. 3,4 In continuation of our previous work on ternary complexes containing nucleotides [5][6][7][8][9] the mixed ligand complexes of the type Ln(III) + nucleotide + zwitterionic buffer ligands (Ln(III) + NU + Z) (see Chart 1) where nucleotide ) AMP, GMP, or CMP, zwitterionic buffer ligands ) MOPSO, MES, ACES, or HEPES, and Ln(III) ) La(III), Ce(III), Pr(III), or Eu(III) have been investigated by potentiometric pH-titrations to determine the formation constants of the normal and protonated mixed ligand complexes formed in solution.…”

Section: Introductionmentioning

confidence: 86%

Ternary Complexes Formed by Trivalent Lanthanide Ions, Nucleotides, and Biological Buffers

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Azab

2001

J. Chem. Eng. Data

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Potentiometric equilibrium measurements have been performed at (25.0 ( 0.1) °C and ionic strength I ) 0.1 mol dm -3 KNO 3 for the interaction of adenosine 5′-monophosphate, guanosine 5′-monophosphate, cytidine 5′-monophosphate, and La(III), Ce(III), Pr(III), and Eu(III) with the biologically important secondary ligand zwitterionic buffers (3-[N-morpholinol])-2-hydroxypropanesulfonic acid, 2-(N-morpholino)ethanesulfonic acid, N-2-acetamido-2-aminoethanesulfonic acid, and N-2-hydroxyethylpiperazine-N-2ethanesulfonic acid. Measurements were made in a 1:1:1 ratio. Formation constants for the monohydroxy, dihydroxy, and dimeric ligand complexes for the binary systems Ln(III) + adenosine 5′-monophosphate, Ln(III) + guanosine 5′-monophosphate, Ln(III) + cytidine 5′-monophosphate, and Ln(III) + zwitterionic buffers have been evaluated. The formation of various 1:1:1 normal and protonated mixed ligand complex species was inferred from the potentiometric pH-titration curves. The experimental conditions were selected such that self-association of the nucleotides and their complexes due to stacking interaction was negligibly small; that is, the monomeric normal and protonated ternary complexes were studied.

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“…Ternary complexes of transition divalent metal ions with AMP, ADP, ATP, and other secondary ligands have been investigated. − For an improved understanding of the mechanism leading to mixed-ligand complexes, the systems M(II) + NU + Z, where NU = AMP, ADP, or ATP, Z = MOPS, AMPSO, HEPPSO, PIPES, or POPSO, and M(II) = Cu(II), Co(II), Ni(II), Mn(II), Zn(II), Ca(II), or Mg(II), have been investigated by potentiometric pH titration. The stability constants of the normal and protonated mixed-ligand complexes formed in solution have been determined.…”

Section: Introductionmentioning

confidence: 99%

“…pH against a volume of 0.0330 mol dm -3 KOH for the Mn(II) + ATP + AMPSO system at (25.0 ( 0.1)°C and I ) 0.1 mol dm -3 KNO3: (a) 0.004 mol dm -3 HNO3 + 0.001 mol dm -3 ATP (2); (b) 0.004 mol dm -3 HNO3 + 0.001 mol dm -3 Mn(II) + 0.001 mol dm -3 ATP (f); (c) 0.004 mol dm -3 HNO3 + 0.001 mol dm -3 AMPSO (+); (d) 0.004 mol dm -3 HNO3 + 0.001 mol dm -3 Mn(II) + 0.001 mol dm -3 AMPSO (]); (e) 0.004 mol dm -3 HNO3 + 0.001 mol dm -3 Mn(II) + 0.001 mol dm -3 ATP + 0.001 mol dm -3 AMPSO (b).HEPPSO, Ca(II) + ATP + HEPPSO, and Mg(II) + ATP + HEPPSO systems, complexation starts at the pH range of 3.6-7 8. Different values for log K and log , which have been calculated and refined using the experimental data, are given inTables1-7.…”

mentioning

confidence: 99%

Role of Biologically Important Zwitterionic Buffer Secondary Ligands on the Stability of the Mixed-Ligand Complexes of Divalent Metal Ions and Adenosine 5‘-Mono-, 5‘-Di-, and 5‘-Triphosphate

2001

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Potentiometric equilibrium measurements have been performed at (25.0 ( 0.1)°C and ionic strength I ) 0.1 mol dm -3 KNO 3 for the interaction of the purine nucleotides adenosine 5′-mono, 5′-di, and 5′-triphosphate and Cu(II), Co(II), Ni(II), Mn(II), Zn(II), Ca(II), and Mg(II) with the biologically important secondary ligand zwitterionic buffers 3-(N-morpholino)propanesulfonic acid, 3-[(1,1-dimethyl-2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid, N-(2-hydroxyethyl)piperazine-N′-2-hydroxypropanesulfonic acid, piperazine-N,N′-bis(2-ethanesulfonic acid), and piperazine-N,N′-bis(2-hydroxypropanesulfonic acid) in a 1:1:1 ratio and the formation of various 1:1:1 normal and protonated mixed-ligand complex species was inferred from the potentiometric pH titration curves. The experimental conditions were selected such that self-association of the purine nucleotides and their complexes was negligibly small; i.e., the monomeric normal and protonated ternary complexes were studied. Initial estimates of the formation constants of the resulting species and the acid dissociation constants of adenosine 5′-mono-, 5′-di-, and 5′-triphosphate and the zwitterionic buffer secondary ligands have been refined with the SUPERQUAD computer program. In some M(II) mixed-ligand systems, the interligand interactions between the coordinate ligands, possibly H bond formation, have been found to be most effective in deciding the stability of the mixed-ligand complexes formed in solutions.

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Potentiometrische Untersuchung der Bildungsgleichgewichte von bin�ren und tern�ren Komplexen von Kobalt(II) mit Adenosin-5?-mono-, -di- und -triphosphat und einigen biologisch bedeutenden polybasischen Sauerstoffs�uren

Cited by 11 publications

References 32 publications

Ternary Complexes in Solution. Comparison of the Coordination Tendency of Some Biologically Important Zwitterionic Buffers toward the Binary Complexes of Some Transition Metal Ions and Some Amino Acids

Ternary Complexes in Solution. Comparison of the Coordination Tendency of Some Biologically Important Zwitterionic Buffers toward the Binary Complexes of Some Transition Metal Ions and Some Amino Acids

Ternary Complexes Formed by Trivalent Lanthanide Ions, Nucleotides, and Biological Buffers

Role of Biologically Important Zwitterionic Buffer Secondary Ligands on the Stability of the Mixed-Ligand Complexes of Divalent Metal Ions and Adenosine 5‘-Mono-, 5‘-Di-, and 5‘-Triphosphate

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