scholarly journals Determination of Acid Dissociation Constant of Ion Exchange Resin by Nuclear Magnetic Resonance

1971 ◽  
Vol 8 (7) ◽  
pp. 377-381 ◽  
Author(s):  
Ken-ichi OCHIAI ◽  
Kunio SETO
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Ion Exchange ◽  
Dissociation Constant ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Nuclear Magnetic

Theoretical calculations of acid-dissociation constants of proteins

1998 ◽  
Vol 76 (2-3) ◽  
pp. 198-209 ◽  
Author(s):  
André H Juffer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dissociation Constants ◽  
Theoretical Calculations ◽  
Acid Dissociation ◽  
Continuum Electrostatics ◽  
Acid Dissociation Constants ◽  
Computational Procedures ◽  
Nuclear Magnetic

The purpose of this review is to introduce several computational procedures for the determination of acid-dissociation constants (pKa) of titratable groups in proteins. Several concepts, such as continuum electrostatics and the exact meaning of intrinsic and apparent pKas, will be explained in some detail. Each of the methods will be judged on its merits, and some comparisons between the methods will be presented. While the emphasis of this review will be on theoretical formulations, the experimental determination by means of nuclear magnetic resonance will be briefly explained. The determination of individual pKa values by nuclear magnetic resonance in combination with computationally determined pKas can provide unique information about the pH-dependent properties of proteins and their complexes with peptides, DNA, and ligands.Key words: acid-dissociation constants, NMR, continuum electrostatics, dielectric constant of proteins, Monte Carlo, molecular dynamics.

Fluorometric Determination of Chlortetracycline in Mixed Feeds

1964 ◽  
Vol 47 (2) ◽  
pp. 203-208
Author(s):  
Stanley E Katz ◽  
Joseph Spock
Keyword(s):  
Ion Exchange ◽  
Exchange Resin ◽  
Ammonium Hydroxide ◽  
Solvent System ◽  
Ion Exchange Resin ◽  
Alkaline Degradation ◽  
Fluorometric Determination ◽  
Mixed Feeds ◽  
Microbiological Assays

Abstract The fluorometric procedure for chlortetracycline in mixed feeds is based upon the degradation of chlortetracycline in alkaline solution to isochlortetracycline. The fluorescence of the isochlortetracycline is directly proportional to the concentration of chlortetracycline present prior to alkaline degradation. Chlortetracycline is extracted from mixed feeds with an acidmethanol solvent system, separated from the feed extract by adsorption on a Dowex 50 ion exchange resin, and eluted from the resin by ammonium hydroxide after conversion to isochlortetracycline. The isochlortetracycline is measured fluorometrically. Recoveries from known feeds are generally greater than 90% and agreements with microbiological assays are very close.

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