The Effects of Optical Configuration of Peptides: Dissociation Constants of the Isomeric Alanylalanines and Leucyltyrosines and Some of their Metal Complexes<sup>1</sup>

Li, N. C.; Miller, Gary W.; Solony, N.; Gillis, B. T.

doi:10.1021/ja01499a066

Cited by 16 publications

(9 citation statements)

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“…On the other hand, the pKal value theoretically obtained (pK a1 = 3.1504) has an adequate agreement with the experimental pK a1 value (pK a1 = 3.7037). We conclude that this fact constitutes a strong support for the reactions and equilibria of ionization selected here [62].…”

Section: First Ionization Constant Of L-phenylalanylglycinesupporting

confidence: 79%

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

Kiani¹,

Tajbakhsh²,

Ashrafi³

et al. 2014

HJBC

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Section: First Ionization Constant Of L-phenylalanylglycinesupporting

confidence: 79%

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

Kiani¹,

Tajbakhsh²,

Ashrafi³

et al. 2014

HJBC

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“…The p K a values of the peptide analytes range between 2.2 and 3.8 24–26. Moreover, all‐ L stereoisomers of small peptides are typically less acidic than the diastereomers with “mixed” stereochemistry of the amino acids 27, 28. Thus, the peptides are positively charged at pH 2–3 while they become increasingly electroneutral zwitterions when increasing the pH of the mobile phase, thus reducing their electrophoretic mobility.…”

Section: Resultsmentioning

confidence: 99%

A weak cation‐exchange monolith as stationary phase for the separation of peptide diastereomers by CEC

Ludewig

Nietzsche

Scriba

2010

J of Separation Science

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A CEC weak cation-exchange monolith has been prepared by in situ polymerization of acrylamide, methylenebisacrylamide and 4-acrylamidobutyric acid in a decanol-dimethylsulfoxide mixture as porogen. The columns were evaluated by SEM and characterized with regard to the separation of diastereomers and α/β-isomers of aspartyl peptides. Column preparation was reproducible as evidenced by comparison of the analyte retention times of several columns prepared simultaneously. Analyte separation was achieved using mobile phases consisting of acidic phosphate buffer and ACN. Under these conditions the peptides migrated due to their electrophoretic mobility but the EOF also contributed as driving force as a function of the pH of the mobile phase due to increasing dissociation of the carboxyl groups of the polymer. Raising the pH of the mobile phase also resulted in deprotonation of the peptides reducing analyte mobility. Due to these mechanisms each pair of diastereomeric peptides displayed the highest resolution at a different pH of the buffer component of the mobile phase. Comparing the weak-cation exchange monolith to an RP monolith and a strong cation-exchange monolith different elution order of some peptide diastereomers was observed, clearly illustrating that interactions with the stationary phase contribute to the CEC separations.

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“…With the exception of a-Asp-PheOMe the elution order can be explained based on the pK a values of the peptide diastereomers. The pK a values of di-and tripeptides range between 2.8 and 3.4 [13,14] and the all-L stereoisomers of small peptides are typically less acidic than the diastereomers with ''mixed'' stereochemistry of the amino acids [15,16]. Therefore, the DL stereoisomers bear a less positive charge at pH 3.0 resulting in a slower electrophoretic mobility compared with the respective LL configured peptides so that the LL diastereomers elute first.…”

Section: Separation Of Diastereomers Of Dipeptidesmentioning

confidence: 99%

“…CEC on the hydrophobic monolith also allowed the separation of the diastereomers of the 24mer peptides tetracosactide and 16 [D-Lys]-tetracosactide (Fig. 5A).…”

Section: Separation Of Diastereomers Of Dipeptidesmentioning

confidence: 99%

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Separation of peptide diastereomers using CEC and a hydrophobic monolithic column

Ludewig¹,

Dong

Zou

et al. 2010

J of Separation Science

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A neutral hydrophobic monolith prepared by radical in situ copolymerization of lauryl methacrylate and ethylene dimethacylate has been evaluated for the CEC separation of diastereomers of small peptides using acidic mobile phases containing ACN as organic modifier. Using an acidic mobile phase, the peptides migrated due to their own electrophoretic mobility. Hydrophobic interactions with the stationary phase contributed to the separation. Peptide mobility and resolution increased with increasing the ACN content. Retention times increased with the pH of the mobile phase. Peak resolution increased with buffer pH and concentration. Di- and tripeptides composed only of L-configured amino acids migrated faster than peptides containing D-amino acids. A mixture of isomeric Asp tripeptides that could not be completely resolved by either CZE or HPLC as well as the 24mer peptides tetracosactide and (16)[D-Lys]-tetracosactide could also be separated by CEC on the hydrophobic monolith.

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The Effects of Optical Configuration of Peptides: Dissociation Constants of the Isomeric Alanylalanines and Leucyltyrosines and Some of their Metal Complexes¹

Cited by 16 publications

References 0 publications

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

A weak cation‐exchange monolith as stationary phase for the separation of peptide diastereomers by CEC

Separation of peptide diastereomers using CEC and a hydrophobic monolithic column

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The Effects of Optical Configuration of Peptides: Dissociation Constants of the Isomeric Alanylalanines and Leucyltyrosines and Some of their Metal Complexes1

Cited by 16 publications

References 0 publications

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

A weak cation‐exchange monolith as stationary phase for the separation of peptide diastereomers by CEC

Separation of peptide diastereomers using CEC and a hydrophobic monolithic column

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The Effects of Optical Configuration of Peptides: Dissociation Constants of the Isomeric Alanylalanines and Leucyltyrosines and Some of their Metal Complexes¹