Experimental analysis of protein precipitation by polyethylene glycol and comparison with theory

Mahadevan, Hari; Hall, Carol K.

doi:10.1016/0378-3812(92)87043-m

Cited by 32 publications

(28 citation statements)

References 24 publications

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“…14,15 The poor correlations between stress at break and dry fiber diameter that were found in this study for the low-molecular-weight PEGs further enhanced the previous observations.…”

Section: Influence Of Peg 200 Peg 1k and Peg 8ksupporting

confidence: 83%

Engineering extruded collagen fibers for biomedical applications

Zeugolis

Paul

Attenburrow

2008

J of Applied Polymer Sci

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Extruded collagen fibers constitute a promising biomimetic scaffold for tissue engineering applications. In this study, we compared the structural, thermal, and mechanical properties of fibers produced from either NaCl or poly(ethylene glycol) with a number-average molecular weight of 8000 (PEG 8K), the only two coagents that have been used in the fabrication process. As novel, we report the fabrication of fibers with properties similar to native or synthetic fibers using other coagents. NaCl derived fibers were characterized by higher thermal stability (p < 0.026), stress (p < 0.001), and modulus (p < 0.0025) values than PEG 8K, whereas the latter yielded more extendable fibers (p < 0.012). Poly(ethylene glycol)s with number-average molecular weights of 200 and 1000 produced fibers with similar mechanical properties (p > 0.05) that were thinner (p < 0.033), stiffer (p < 0.022), and less extendable (p < 0.0002) than those of PEG 8K. Poly(vinyl alcohol) (PVA) with a numberaverage average molecular weight of 9-10,000 and PEG 8K yielded fibers with similar diameters and stress-at-break values (p > 0.05); however, the poly(ethylene glycol) derived fibers were more extendable (p < 0.0003), whereas the PVA fibers were stiffer (p < 0.029). Gum-arabic-and solublestarch-derived fibers were of similar tensile strength, extendibility, and stiffness (p > 0.05). In this in vitro study, the thickest (p < 0.011) and the weakest (p < 0.0066) fibers were produced in the presence of sodium sulfate.

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“…14,15 The poor correlations between stress at break and dry fiber diameter that were found in this study for the low-molecular-weight PEGs further enhanced the previous observations.…”

Section: Influence Of Peg 200 Peg 1k and Peg 8ksupporting

confidence: 83%

Engineering extruded collagen fibers for biomedical applications

Zeugolis

Paul

Attenburrow

2008

J of Applied Polymer Sci

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“…Lysozyme 91 ðCl; phosphateÞ 9-: l 23 5v 1 l pi 23 1l ev 23 51:03N 3 -0:17 ðNa 1 Þ 14 BSA 14-: l 23 5v 1 l pi 23 1l ev 23 53:2N 3 -0:92 (8) where the units of l 2 are kcal mol 21 molal 21 . The intercepts in Eq.…”

Section: Separating Chemical and Excluded Volume Effects Of Polyethylmentioning

confidence: 99%

Separating chemical and excluded volume interactions of polyethylene glycols with native proteins: Comparison with PEG effects on DNA helix formation

2015

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Small and large PEGs greatly increase chemical potentials of globular proteins (μ2), thereby favoring precipitation, crystallization, and protein-protein interactions that reduce water-accessible protein surface and/or protein-PEG excluded volume. To determine individual contributions of PEG-protein chemical and excluded volume interactions to μ2 as functions of PEG molality m3, we analyze published chemical potential increments μ23 = dμ2/dm3 quantifying unfavorable interactions of PEG (PEG200-PEG6000) with BSA and lysozyme. For both proteins, μ23 increases approximately linearly with the number of PEG residues (N3). A 1 molal increase in concentration of PEG -CH2OCH2- groups, for any chain-length PEG, increases μBSA by ~2.7 kcal/mol and μlysozyme by ~1.0 kcal/mol. These values are similar to predicted chemical interactions of PEG -CH2OCH2- groups with these protein components (BSA ~3.3 kcal/mol, lysozyme ~0.7 kcal/mol), dominated by unfavorable interactions with amide and carboxylate oxygens and counterions. While these chemical effects should be dominant for small PEGs, larger PEGS are expected to exhibit unfavorable excluded volume interactions and reduced chemical interactions because of shielding of PEG residues in PEG flexible coils. We deduce that these excluded volume and chemical shielding contributions largely compensate, explaining why the dependence of μ23 on N3 is similar for both small and large PEGs.

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“…The theory of aqueous protein solubility has also attracted attention [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. In this paper, two of the most promising approaches are reviewed.…”

Section: Introductionmentioning

confidence: 98%