Characteristics of kinetically controlled Bridička currents observed with bovine serum albumin in ammonia and triethylamine buffers

Kolthoff, I. M.; Yamashita, Kazuo; Hie, Tan Boen; Kanbe, Akira

doi:10.1016/s0022-0728(74)80079-3

Cited by 11 publications

(2 citation statements)

References 22 publications

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“…The above medium originally proposed by Brdička [2] does not seem to be the best for the analysis of proteins because of its poorly controlled and rather high pH (about 9.5). Different media were therefore suggested by other authors [19,[26][27][28][29][30][31]. Here we use the medium containing 1 mM [Co(NH 3 ) 6 ] 3þ in glycine buffer, pH 8.5 [32].…”

Section: Catalytic Hydrogen Reduction In Cobalt-containing Solutionsmentioning

confidence: 99%

Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

et al. 1998

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Constant current derivative chronopotentiometric stripping analysis (CPSA) was used to study bioactive peptides [Lys 8 ]-vasopressin and angiotensin II at carbon paste electrode (CPE) and hanging mercury drop electrode (HMDE). Both peptides contain a single tyrosine residue which is oxidized at CPE close to þ0.6 V (against Ag/AgCl/3 M KCl electrode) producing peak Y; this peak was by about 15 mV more positive in vasopressin than in angiotensin II. At HMDE vasopressin yielded peak S due to the reduction of the disulfidic bond in the peptide. No peak S was observed with angiotensin II as it does not contain any cystine/cysteine residues. Vasopressin produced different catalytic hydrogen reduction signals in media with cobalt ion and in media not containing any metal ion. The signal produced in the latter media (peak H), which appeared close to ¹1.7 V, was well separated from the background. No catalytic hydrogen reduction signal was obtained with angiotensin II. The above mentioned CPSA signals can be applied for the determination of the respective peptide at nanomolar concentrations. The least sensitive peak S appears which requires at least 100 nM vasopressin concentration at moderate accumulation time. By two orders of magnitude, higher sensitivities can be obtained with peaks Y and H. In measuring these peaks CPSA shows significant advantages over the voltammetric stripping techniques.

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Section: Catalytic Hydrogen Reduction In Cobalt-containing Solutionsmentioning

confidence: 99%

Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

et al. 1998

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“…Characteristics of Brdicka currents (3)(4)(5)(6) and of presodium currents (7) under various conditions, also in the presence of various concentrations of urea (8), have been presented in previous publications. A few experiments have also been carried out on the effects on Abbreviations: BSA, bovine-serum albumin; TEAP, tetraethylammonium perchlorate; TMAC, tetramethylammonium chloride; TEAC, tetraethylammonium chloride; TPAB, tetrapropylammonium bromide; TBAB, tetrabutylammonium bromide; SCE, saturated calomel electrode; DME, dropping mercury electrode; -ipL presodium current.…”

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confidence: 99%

Effects of tetraalkylammonium salts on Brdicka and presodium currénts of bovine-serum albumin.

Kolthoff¹,

Yamashita²

1975

Proc. Natl. Acad. Sci. U.S.A.

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Tetraethyl-, tetrapropyl-, and tetrabutylammonium ions are capillary-active on the interface water-mercury. In the adsorbed state they increase Brdicka and presodium currents. These currents drop sharply at potentials where tetrabutylammonium ions are desorbed, these potentials being -1.60, -1.66, -1.72, and -1.79 V versus the saturated calomel electrode (SCE) at tetrabutylammonium concentrations of 0.1, 0.25, 1, and 5 mM, respectively. Indications are that tetraethylammonium ions at a concentration of 50 mM are desorbed at a potential of the order of -1.9 V (versus SCE). Tetraethyl-, tetrapropyl-, and tetrabutylammonium salts are adsorbed from aqueous solutions on the surface of mercury. Mairanovskii and Churilina (1) report that these tetraalkylammonium ions have a significant effect on the kinetics and mechanism of electrode processes. Pungor and Farsang (2) found that at low concentrations tetraalkylammonium salts cause an increase in the catalytic hydrogen waves (comparable to "presodium" currents of bovine-serum albumin, BSA) of quinine, nicotinamide, and methylene blue in phosphate buffers. In order to explain the results by these authors, Mairanovskii et al. (1) studied the effect of tetraethylammonium perchlorate (TEAP) on catalytic hydrogen waves observed with pyridine and 2,6-lutidine in various buffers at the dropping mercury electrode. Under specified conditions they found an increase of the catalytic waves at concentrations of TEAP (10-40 mM). In general, they attribute the effect of TEAP to a retardation of electrochemical reactions by a film of cations adsorbed on the electrode, by a change in the electrokinetic potential, and by a specific action which is not completely understood.It appeared of interest to study the effects of tetraalkylammonium salts on Brdicka and presodium currents observed with BSA in various buffers. Characteristics of Brdicka currents (3-6) and of presodium currents (7) under various conditions, also in the presence of various concentrations of urea (8), have been presented in previous publications. A few experiments have also been carried out on the effects on Abbreviations: BSA, bovine-serum albumin; TEAP, tetraethylammonium perchlorate; TMAC, tetramethylammonium chloride; TEAC, tetraethylammonium chloride; TPAB, tetrapropylammonium bromide; TBAB, tetrabutylammonium bromide; SCE, saturated calomel electrode; DME, dropping mercury electrode; -ipL presodium current.Brdicka and presodium currents of BSA of tetraphenylarsonium ions, tetramethylguanidine, and diphenylguanidine, all capillary-active on the interface mercury-water. Finally, the effect of tetrabutylammonium ions on Brdicka currents of cysteine in the presence of cobalt(II) is described. EXPERIMENTAL Samples of BSA and several chemicals used have been described previously (3). Tetramethylammonium chloride (TMAC), tetraethylammonium chloride (TEAC), tetrapropylammonium bromide (TPAB), and tetrabutylammonium bromide (TBAB) were pure products from various firms. Details regarding the polarograph used and th...

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4.50—Polarographic investigation of conformational changes of human serum albumin

Chmelı́k

Kalous

1982

Journal of Electroanalytical Chemistry and Interfacial Electroc

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Characteristics of kinetically controlled Bridička currents observed with bovine serum albumin in ammonia and triethylamine buffers

Cited by 11 publications

References 22 publications

Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

Effects of tetraalkylammonium salts on Brdicka and presodium currénts of bovine-serum albumin.

4.50—Polarographic investigation of conformational changes of human serum albumin

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