Anion Chromatography with low-conductivity eluents. II.

Gjerde, Douglas T.; Fritz, James S.; Schmuckler, G.

doi:10.1016/s0021-9673(00)87871-1

Cited by 297 publications

(92 citation statements)

References 2 publications

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“…Ions have been observed to impact protein stability, 3 fibril formation, [4][5][6] reversible self-association, [7][8][9] and even protein solution rheology. 10,11 An ion-specific dependence is often discussed in terms of the Hofmeister effect or the electroselectivity series; [3][4][5][12][13][14] however, the exact nature of ion-protein interactions remains unresolved. The classical view holds that such interactions are mediated indirectly through the alteration of bulk water structure, 15 although there is increasing recognition that ions interact directly with proteins.…”

Section: Introductionmentioning

confidence: 99%

Ion‐specific modulation of protein interactions: Anion‐induced, reversible oligomerization of a fusion protein

et al. 2008

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Ions can significantly modulate the solution interactions of proteins. We aim to demonstrate that the salt-dependent reversible heptamerization of a fusion protein called peptibody A or PbA is governed by anion-specific interactions with key arginyl and lysyl residues on its peptide arms. Peptibody A, an E. coli expressed, basic (pI 5 8.8), homodimer (65.2 kDa), consisted of an IgG1-Fc with two, C-terminal peptide arms linked via penta-glycine linkers. Each peptide arm was composed of two, tandem, active sequences (SEYQGL PPQGWK) separated by a spacer (GSGSATGGSGGGASSGSGSATG). PbA was monomeric in 10 mM acetate, pH 5.0 but exhibited reversible self-association upon salt addition. The sedimentation coefficient (s w ) and hydrodynamic diameter (D H ) versus PbA concentration isotherms in the presence of 140 mM NaCl (A5N) displayed sharp increases in s w and D H , reaching plateau values of 9 s and 16 nm by 10 mg/mL PbA. The D H and sedimentation equilibrium data in the plateau region (>12 mg/mL) indicated the oligomeric ensemble to be monodisperse (PdI 5 0.05) with a z-average molecular weight (M z ) of 433 kDa (stoichiometry 5 7). There was no evidence of reversible selfassociation for an IgG1-Fc molecule in A5N by itself or in a mixture containing fluorescently labeled IgG1-Fc and PbA, indicative of PbA self-assembly being mediated through its peptide arms. Self-association increased with pH, NaCl concentration, and anion size (I 2 > Br 2 > Cl 2 > F 2 ) but could be inhibited using soluble Trp-, Phe-, and Leu-amide salts (Trp > Phe > Leu). We propose that in the presence of salt (i) anion binding renders PbA self-association competent by neutralizing the peptidyl arginyl and lysyl amines, (ii) self-association occurs via aromatic and hydrophobic interactions between the ..xx ..xxx.. xx.. motifs, and (iii) at >10 mg/mL, PbA predominantly exists as heptameric clusters.Keywords: Hofmeister series; electroselectivity series; self-association; ion-protein interactions; anion binding; dynamic light scattering; analytical ultracentrifugation Abbreviations: A5, 10 mM acetate buffer at pH 5.0; A5N, 10 mM acetate buffer at pH 5.0 containing 140 mM sodium chloride;

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Section: Introductionmentioning

confidence: 99%

Ion‐specific modulation of protein interactions: Anion‐induced, reversible oligomerization of a fusion protein

et al. 2008

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“…Initially, HPLC was applied to the separation and identification of mainly organometals and/or metal chelates/complexes. Within the past few years, a tremendous interest has emerged towards inorganic metal cation/anion analyses, especially in the use of ion chromatography (IC) and/or high performance ion-exchange type chromatography, together with conductivity and/or electrochemical detection (15,(20)(21)(22)(32)(33)(34)(35)(36)(37)(38)(39). It has become obvious that Ie, especially via the use of commercially available instrumentation, has become quite popular, very useful, and can be readily utilized with pre-concentration methods for trace environmental and/or toxicological studies.…”

Section: Introduction (1)mentioning

confidence: 99%

“…In t h e recent past, others have b r i e f l y reported on the use o f such approaches f o r the separation o f various cations and anions, but such work was most o f t e n not i n t e r f a c e d w i t h the l a t e s t advances i n I C P detection. That work which has used ion-exchange HPLC and/or chelation chromatography has generally used c o n d u c t i v i t y detection, atomic absorption spectroscopy, and/or electrochemical detection (8)(9)(10)(11)(12)(13)(14)(15)(16)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39).…”

Section: Introduction (1)mentioning

confidence: 99%

Metal Cation/Anion Speciation via Paired-Ion, Reversed Phase HPLC with Refractive Index and/or Inductively Coupled Plasma Emission Spectroscopic Detection Methods

Savage

Bushee²,

Krull

et al. 1982

Journal of Liquid Chromatography

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Conventional high performance 1 i qu i d chromatography instrumentation and packing materials can be inexpensively and rapidly utilized for the qualitative and quantitative analysis of various metal cations or anions. The final approaches utilize reversed phase HPLC in the form of paired-ion separations. The detection of individually eluted, fully resolved metal cations or anions is possible conventional refractive index or inductively coupled plasma emission spectroscopic detection. In many cases, unresolved mixtures of metal cations, eluted as a single peak on HPLC, can be resolved and identified via the use of ICP detection. Both metal cations and anions can be easily resolved, according to oxidation states, using paired-ion techniques, in combination with ICP detection. Final data representation can be in the form of conventional, continuous RI and/or ICP chromatograms, pulsed data ICP presentations, and/or tabular ICP data presentation.INTRODUCTION (1) Inorganic metal toxicity has long been an area of intense biological,

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“…2.5, the slope of log k/log C (k: retention factor of analyte; C: molar concentration of eluting ion) for monovalent anion should be -0.4, assuming that the separation is based only on the ion-exchange mode. 12 However, because the calculated values were -0.17 (H2PO4 -), -0.22 (Cl -), -0.38 (NO2 -), -0.31 (Br -), -0.30 (NO3 -), and -0.36 (SO4 2-), another retention parameter must participate in the separation. Figure 3 shows a chromatogram of common anions using 1.5 mM 5-sulfoisophthalic acid, with a background conductivity of ca.…”

Section: Column Selectionmentioning

confidence: 95%

Optimum Combination of Column and Eluent for High-Sensitivity Non-Suppressed Ion Chromatography of Common Anions

2000

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In non-suppressed ion chromatography (IC), the conductivity detection sensitivity of anions is generally less than that of cations. This is due to the difference in the molar conductivities between analyte and eluting ions. On the one hand, anion IC often gives a second system peak due to the distribution of the conjugate acid of the eluting ion to the stationary phase, 1-3 in addition to the first system peak (water dip). In previous work, 4,5 we proved that the detection sensitivities of inorganic common anions eluted between the void and the second system peak are significantly increased by using an organic strong acid, such as 5-sulfoisophthalic acid, 5 as the eluent. This effect is based on the distribution of the undissociated strong acid (conjugate acid of the eluting ion) to the stationary phase hydrophobically, which is very different from another increase in sensitivity proposed by Gjerde and Fritz 6 using benzoic acid as the eluent, based on a sift of the dissociation equilibrium of a weak acid in the mobile phase.Although our proposed method is more practical because the separation window is relatively wide, i.e., the advent of the 2nd system peak can be delayed, there has been a weak point in that the peaks of the chloride and nitrite ions overlap when using a commercially available anion-exchange column. In order to solve this problem, another high-resolution column must be found.On the other hand, high-efficiency ion-exchange columns could be prepared by modifying a conventional octadecyl-silica (ODS) column with a highly hydrophobic ionic surfactant, which were applied to the separation of common anions. [7][8][9][10]

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Anion Chromatography with low-conductivity eluents. II.

Cited by 297 publications

References 2 publications

Ion‐specific modulation of protein interactions: Anion‐induced, reversible oligomerization of a fusion protein

Ion‐specific modulation of protein interactions: Anion‐induced, reversible oligomerization of a fusion protein

Metal Cation/Anion Speciation via Paired-Ion, Reversed Phase HPLC with Refractive Index and/or Inductively Coupled Plasma Emission Spectroscopic Detection Methods

Optimum Combination of Column and Eluent for High-Sensitivity Non-Suppressed Ion Chromatography of Common Anions

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