Micellar electrokinetic chromatographic study of the interaction between enkephalin peptide analogs and charged micelles

Fürtös‐Matei, Alexandra; Li, Jianjun; Waldron, Karen C.

doi:10.1016/s0378-4347(97)00147-3

Cited by 22 publications

(20 citation statements)

References 33 publications

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“…We previously observed behavior consistent with strong electrostatic interactions in MEKC studies of enkephalin analogs [16]. Binding to SDS micelles increased (observed as shifts in the absolute electrophoretic mobility) as pH decreased from 8.9 to 5.4 (pI 5.4) because the protonated N-terminal amine interacted with the anionic micelle.…”

Section: Resultssupporting

confidence: 62%

“…When Terabe's group [13,14] demonstrated micellar electrokinetic capillary chromatography (MEKC) in the mid-1980s, it was expected to rival liquid chromatography (LC) for the analysis of amino acids and peptides. In reality, MEKC using charged micelles can be problematic for the separation of complex mixtures of peptides [15,16]; their zwitterionic nature leads to strong, yet nonspecific, electrostatic interactions with charged micelles masking weaker hydrophobic effects that make reversed-phase LC selective. This underlines the importance of solution pH.…”

Section: Introductionmentioning

confidence: 99%

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A comparison between electrokinetic capillary chromatography and absorption spectroscopy for the analysis of peptide‐micelle association by weak hydrophobic interactions

2003

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Micellar electrokinetic capillary chromatography (MEKC) was compared to absorption spectroscopy to estimate equilibrium association constans (K(as)) for peptide-micelle systems involving three peptides (leucine-enkephalin, methionine-enkephalin and leucine-phenylalanine (LF)) and two surfactant micelles (sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB)). Buffer pH was chosen to minimize purely electrostatic interactions between peptides and micelles that could not be interrogated by absorption spectroscopy. Viscosity-corrected MEKC mobilities gave reasonably similar estimates of K(as) between the two methods for all three peptide-SDS micelle systems, with K(as) values ranging from 13.7 +/- 0.3 to 49 +/- 1 M(-1). For CTAB, estimates of K(as) for LF-CTAB micelle association were of the same order of magnitude as the SDS micelle by the two methods of estimation. On the other hand, enkephalin-CTAB micelle binding was about 10 times stronger (K(as) = 122 +/- 3 M(-1) to 311 +/- 9 M(-1)) than the enkephalin-SDS micelle binding. In addition, MEKC underestimated the K(as) values relative to spectroscopy by a factor of 2-3 for the enkephalin-CTAB system.

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Section: Resultssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

A comparison between electrokinetic capillary chromatography and absorption spectroscopy for the analysis of peptide‐micelle association by weak hydrophobic interactions

2003

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“…For example, in a mixture containing seven enkephalins, Leu-enkephalin eluted before [D-ala 2 ]-Leu-enkephalin, as would be expected if the later peptide has a larger SDS micelle association constant. 20 In the analysis by Han et al, the elution order of three peptides in Table 1 was as follows: Leu-enkephalin, [D-ala 2 ]-Leuenkephalin, Leu-enkephalin-Lys. Again, the elution order is consistent with the association constants from PFG-NMR diffusion experiments, in that the peptides with smaller K eq values elute before those with larger SDS micelle association constants.…”

Section: Resultsmentioning

confidence: 99%

A pulsed field gradient NMR diffusion investigation of enkephalin peptide‐sodium dodecyl sulfate micelle association

Begotka

Hunsader

Oparaeche

et al. 2006

Magnetic Reson in Chemistry

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Pulsed field gradient NMR (PFG-NMR) diffusion experiments were used to investigate the binding of leucine and methionine enkephalin peptides to anionic sodium dodecyl sulfate (SDS) micelles. The study was undertaken to investigate the mechanism of interaction between enkephalin peptides and SDS micelles and to determine if NMR-derived association constants, K(eq), can predict the elution order in electrokinetic chromatography (EKC). In EKC, peptides are separated on the basis of their interactions with micelles. The Leu-enkephalin peptide-micelle association constant increased from 130 +/- 8 to 1459 +/- 57 and 1744 +/- 64 M(-1), respectively, when an Arg or Lys was added to the C-terminus. The association constant of Leu-enkephalinamide was approximately equal to that of Leu-enkephalin-Arg. Substitution of Phe4 with a Trp or Gly2 with an Ala in the Leu-enkephalin peptides also increased the micelle binding affinity. These results confirm that the interaction of Leu-enkephalin peptides with SDS micelles is largely electrostatic and that the non-polar amino acid side chains interact with the hydrophobic micelle core. The peptide-micelle association constants for the cationic Met-enkephalin peptides were also greater than their zwitterionic counterparts. For example, the Met-enkephalin K(eq) value was 162 +/- 9 M(-1), while the association constants for Met-enkephalin-Arg, Met-enkephalin-Lys, and Met-enkephalinamide were, respectively, 674 +/- 31, 426 +/- 23, and 453 +/- 27 M(-1). In both Met-enkephalin and Met-enkephalinamide, replacing Gly2 with an Ala did not significantly increase the association constant. These results confirm that with the Met-enkephalin peptides, there was little or no interaction of the amino acid side chains with the micelle core. For both the Leu-enkephalin and Met-enkephalin peptides, the association constants were consistent with EKC results, in that the peptides with smaller K(eq) values were found to elute before those with larger association constants.

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“…1. All the peptides have pI s of 5.35 -6.1 according to the different literature resources [12,24,25], except the ones containing arginine and lysine (whose pI values were 9.8 [24]), so they are positively charged and migrated before EOF at low pH. It can be seen from (10) were not separated that well at pH a3, while at pH A3.7 peptides Des-tyr 1 -methionine enkephalin (D) (4) and LE (6), methionine enkephalin (ME) (8) and D-AL (9) comigrated.…”

Section: Running Buffer Phmentioning

confidence: 99%

Separation and determination of enkephalin-related peptides using capillary electrophoresis

et al. 2005

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CZE with UV-absorption detection has been used for the separation and determination of enkephalin-related peptides. The experimental conditions, such as pH and concentration of running buffer, applied voltage, injection method, and time, were investigated in detail. Excellent separation efficiency could be obtained for ten enkephalin-related peptides with a 50 microm (ID) x 58 cm capillary using sodium dihydrogen phosphate as the running buffer (pH 3.11) when 20 kV of applied voltage was used. The concentration detection limits were found to be in the range of 0.31-1.94 microg/mL (defined as S/N = 3). The proposed method has been applied to analyze the spiked cerebrospinal fluid (CSF) sample, and the results showed that CZE is a powerful technique for separation and detection of the above biological peptides.

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Micellar electrokinetic chromatographic study of the interaction between enkephalin peptide analogs and charged micelles

Cited by 22 publications

References 33 publications

A comparison between electrokinetic capillary chromatography and absorption spectroscopy for the analysis of peptide‐micelle association by weak hydrophobic interactions

A comparison between electrokinetic capillary chromatography and absorption spectroscopy for the analysis of peptide‐micelle association by weak hydrophobic interactions

A pulsed field gradient NMR diffusion investigation of enkephalin peptide‐sodium dodecyl sulfate micelle association

Separation and determination of enkephalin-related peptides using capillary electrophoresis

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