ChemInform Abstract: Kinetics and Mechanisms of Aqueous Chlorine Reactions with Chlorite Ion in the Presence of Chloride Ion and Acetic Acid/Acetate Buffer.

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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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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Hydrogen Isotope Exchange in 2-Butanone. Further Measurements and Some Comments

Canadian Journal of Chemistry ◽

10.1139/v72-516 ◽

1972 ◽

Vol 50 (19) ◽

pp. 3239-3241 ◽

Cited By ~ 1

Author(s):

R. A. Cox ◽

J. W. Thorpe ◽

J. Warkentin

Keyword(s):

Acetic Acid ◽

Temperature Dependence ◽

Rate Constants ◽

Hydrogen Isotope ◽

Isotope Exchange ◽

Relative Rate ◽

Aqueous Media ◽

Acetate Buffer ◽

Isokinetic Temperature ◽

Relative Rate Constants

The ratio of rate constants for exchange at the methylene and methyl positions of butanone, [Formula: see text], is shown to be near 1.69 in 1:1 acetic acid–acetate buffer; nearly twice the value (0.86) for deuterioxide catalysis at 54.8°. Methods of obtaining rate constants for acetate catalysis from composite rates (acetate and deuterioxide), or from rates in buffered media, are shown to be adequate for estimating rate ratios.Detailed temperature dependence of the relative rate constants for either system is not yet available but the effects are known to be small. For butanone enolizations the isokinetic temperature is in the neighborhood of 35°, when reaction is catalyzed by deuterioxide in aqueous media.

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