High-molecular-weight carrier ampholytes for isoelectric focusing of peptides

Righetti, Pier Giorgio

doi:10.1016/0165-022x(81)90036-1

Cited by 20 publications

(2 citation statements)

References 31 publications

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“…We could also mention here a number of other attempts at 'homemade' products, notably by Vinogradov et al [19], Righetti et al [20], Charlionet et al [21,22] and Just [23]. Other variants introduced by Righetti's group include CAs containing a blend of acrylic and itaconic acid residues hooked onto the oligo-amino backbone, for widening the range of pK values of carboxyl groups buffering in the pH 3-6 region [24], as well as high-M r CAs, made by coupling acrylic acid to polyethylene imine, for the analysis of peptides [25]. In recent times, other patents have been issued claiming better syntheses of CAs.…”

Section: Introductionmentioning

confidence: 99%

Carrier ampholytes for IEF, on their fortieth anniversary (1967–2007), brought to trial in court: The verdict

et al. 2007

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The present review summarizes the data accumulated in 1-year work, by exploring, via a 3-D methodology (Rotofor fractionation followed by CE-MS), all the narrow (2 pH unit wide) carrier ampholyte (CA) compounds for IEF, produced by three companies (Pharmacia with Pharmalyte and Ampholine, BioRad with Bio-Lyte and Serva with Servalyt). All species have been assessed by measuring the types of pH gradient produced, the total number of individual chemicals (with M(r) values) and isoforms and their focusing behavior ('good' or 'poor' ampholytes). Servalyt contains a grand total of 686 chemical entities and no less than 3899 isoforms; Pharmalyte 643 and 2211; Bio-Lyte 255 and 1192; Ampholine 294 and 1182, respectively. In terms of M(r) distribution, although all 2-pH-unit ranges start with the same low M(r) values (ca. 200) their upper limits are quite different. Thus, Pharmalyte reaches an upper M(r) value of 1179 (in the pH 4-6 range), versus 907 for Servalyt, 835 for Bio-Lyte and 893 for Ampholine. In general, in going towards the more alkaline pH intervals (e.g. pH 8-10) the molecular mass of carrier ampholytes (CAs) is reduced to as low as 491 (Bio-Lyte), indicating that the alkaline species are probably made with shorter oligoamines and are, in general, less substituted. All acidic pH intervals (up to pH 6-8) appear to be constituted by a very large proportion of well focusing species, indicating small values of DeltapK across their pI. Above pH 8, all brands of CAs worsen, the vast majority being unable to focus properly and sustain adequately the pH gradient. General guidelines are given for the synthesis of new alkaline species for improving the basic pH ranges.

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Section: Introductionmentioning

confidence: 99%

Carrier ampholytes for IEF, on their fortieth anniversary (1967–2007), brought to trial in court: The verdict

et al. 2007

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“…We could also mention here a number of other attempts at "home-made" products, notably by Vinogradov et al [15], Righetti et al [16], Charlionet et al [17,18] and Just [19]. Other variants introduced by Righetti's group include CAs containing a blend of acrylic and itaconic acid residues hooked onto the oligoamino back-bone, for widening the range of pK values of carboxyl groups buffering in the pH 3-6 region [20], as well as high-M r CAs, made by coupling acrylic acid to polyethylene imine, for analysis of peptides [21].…”

Section: Introductionmentioning

confidence: 99%

Mass distribution, polydispersity and focusing properties of carrier ampholytes for IEF II: pH 4–6 intervals

et al. 2006

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For studying the M(r) distribution and number of species in narrow-range (2 pH-unit wide, in the nominal pI 4-6 interval) carrier ampholytes from four commercial sources (Bio-Lyte, Servalyt, Ampholine and Pharmalyte), a 2-D technique was adopted consisting of a focusing step in a liquid phase (Rotofor, yielding 20 fractions) followed by orthogonal CE in both, acidic and basic buffers. As a final step, every other fraction was analyzed by CE-MS. The findings: Ampholine contains 80 different M(r) compounds, in the M(r) interval 203 to 893 Da, for a total of 325 isoforms. Bio-Lyte consists of 66 different M(r) species, in the M(r) range 388 to 835 Da, for a total of 436 isoforms. Servalyt is made of 199 different M(r) compounds, in the M(r) interval 204 to 907 Da, for a total of 1302 isoforms. Pharmalyte pH 4-6.5, comprises 217 amphoteres, in the M(r) range 150 to 1179 Da, for a total of 812 isoforms. Pharmalyte appears to be the best brand, with the vast majority of species focusing sharply at their pI position and <5% "poor" species, distributed along the entire pH gradient, denoting an extremely shallow pH/mobility curve across the pI value.

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Isoelectric Focusing

2016

Electrophoresis in Practice

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High-molecular-weight carrier ampholytes for isoelectric focusing of peptides

Cited by 20 publications

References 31 publications

Carrier ampholytes for IEF, on their fortieth anniversary (1967–2007), brought to trial in court: The verdict

Carrier ampholytes for IEF, on their fortieth anniversary (1967–2007), brought to trial in court: The verdict

Mass distribution, polydispersity and focusing properties of carrier ampholytes for IEF II: pH 4–6 intervals

Isoelectric Focusing

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