Oxidation of S(IV) by the dodecatungstocobaltate(III) ion over an extended pH range using acetic acid–acetate buffer: Different kinetics, oxidation product and mechanism

The electron microprobe was used to analyze the calcium and phosphorus concentrations of sound, acid-etched, and remineralized enamel. By use of a weak acetic acid-potassium acetate buffer, it was found that the demineralization probably affected only the first 10 micrometers of the enamel surface. This demineralized enamel was successfully remineralized by the use of a calcifying solution. The changes in calcium and phosphorus concentrations and the Ca/P ratios were determined.

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Effect of hydrogen ion changes on vascular resistance in isolated artery segments

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1964.207.1.169 ◽

1964 ◽

Vol 207 (1) ◽

pp. 169-172 ◽

Cited By ~ 12

Author(s):

Oliver Carrier ◽

Meredith Cowsert ◽

John Hancock ◽

Arthur C. Guyton

Keyword(s):

Acetic Acid ◽

Lactic Acid ◽

Sulfuric Acid ◽

Nitric Acid ◽

Perfusion Pressure ◽

Control Level ◽

Linear Increase ◽

Hydrogen Ion ◽

Isolated Artery ◽

Ph Range

Isolated arterial segments, 1 cm in length and 0.5–1.0 mm in diameter, were perfused with Tyrode's solution titrated to various levels of pH. Po2, Pco2, and temperature were held at physiological levels; the perfusion pressure was held at 100 mm Hg, and flow was measured by a drop counter. There was a linear increase in flow as the pH was decreased from 7.4, 0.05 units at a time, with an increase of 87% obtained at pH 7.15. As the pH was further decreased, the flow dropped until at pH 6.8 it leveled off slightly above control level. When the pH was raised, there was an initial 35% decrease in flow by the time pH 7.50 was reached, followed by an increase, reaching 50% above control level at 7.65. At still higher pHs a precipitous decrease in conductance occurred, flow leveling off slightly below control level at pH 7.80. Consistent results were obtained on 45 vessels using Tyrode's solution titrated to the desired pH with lactic acid, hydrochloric acid, acetic acid, sulfuric acid, nitric acid, sodium hydroxides, or sodium bicarbonate. These results indicate that vessels have a very narrow pH range in which they maintain physiological tone.

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Chromatographic Fractionation of the Acetic Acid Soluble Proteins of Wheat Flour on Carboxymethyl-Cellulose

Australian Journal of Biological Sciences ◽

10.1071/bi9610690 ◽

1961 ◽

Vol 14 (4) ◽

pp. 690 ◽

Cited By ~ 14

Author(s):

DH Simmond ◽

DJ Winzor

Keyword(s):

Acetic Acid ◽

Wheat Flour ◽

Carboxymethyl Cellulose ◽

Soluble Proteins ◽

Protein Precipitation ◽

Acetate Buffer ◽

Dimethyl Formamide ◽

Chromatographic Fractionation ◽

Chromatographic Procedure

The acetic acid soluble proteins extracted from wheat flour have been separated into 11 fractions by a chromatographic procedure using columns of carboxymethyl- cellulose, equilibrated with O� 005M acetate buffer, pH 4�1. Under theso conditions one fraction passes unretarded through the column. Eight further fractions are eluted at pH 4� 1 by employing a gradient to O� 2M N aCl in the presence of 1M dimethyl formamide (DMF) which prevents protein precipitation at ionic strengths greater than 0�03.

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A method for the separation of peptides and α-amino acids

Biochemical Journal ◽

10.1042/bj1070335 ◽

1968 ◽

Vol 107 (3) ◽

pp. 335-340 ◽

Cited By ~ 22

Author(s):

D. K. J. Tommel ◽

J. F. G. Vliegenthart ◽

T. J. Penders ◽

J F Arens

Keyword(s):

Amino Acids ◽

Acetic Acid ◽

Glutamic Acid ◽

Aspartic Acid ◽

Acetate Buffer ◽

Acid Fraction ◽

Peptide Fraction ◽

Acidic Peptide ◽

Peptide Fractions ◽

Acetate Form

1. Peptides and α-amino acids, occurring in mixtures from various sources, can be separated into one fraction containing the amino acids and several peptide fractions. This is achieved by chelation of the mixture with Cu2+ ions and subsequent chromatography of these chelates over the acetate form of diethylaminoethylcellulose or triethylaminoethylcellulose. 2. The amino acid fraction is obtained by elution with 0·01m-collidine–acetate buffer, pH8·0. 3. Peptide fractions are eluted with 0·01m-collidine–acetate buffer, pH4·5, 0·17n-acetic acid and 0·1n-hydrochloric acid respectively. 4. With the exception of aspartic acid and glutamic acid, which are partly found in the acidic peptide fraction, the amino acids are completely separated from the peptides. 5. Contamination of the acidic peptide fraction with glutamic acid and aspartic acid can be largely avoided by previous addition of an excess of arginine. 6. Copper is removed from the eluates by extraction with 8-hydroxyquinoline in chloroform.

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