Light scattering and phase behavior of lysozyme-poly(ethylene glycol) mixtures

Light scattering and phase behavior of lysozyme-poly(ethylene glycol) mixtures
Engineering Village 2
2006 Elsevier Inc.
Accession number: 06109753532

Title: Light scattering and phase behavior of lysozyme-poly(ethylene glycol) mixtures

Authors: Bloustine, J.; Virmani, T.; Thurston, G.M.; Fraden, S.

Author affiliation: Complex Fluids Group, Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454, United States

Serial title: Physical Review Letters

Abbreviated serial title: Phys Rev Lett

Volume: v 96

Issue: n 8

Publication year: 2006

Pages: p 087803

Language: English

ISSN: 0031-9007


Document type: Journal article (JA)

Publisher: American Physical Society, College Park, MD 20740-3844, United States

Abstract: Measurements of liquid-liquid phase transition temperatures (cloud points) of mixtures of a protein (lysozyme) and a polymer, poly(ethylene glycol) (PEG) show that the addition of low molecular weight PEG stabilizes the mixture whereas high molecular weight PEG was destabilizing. We demonstrate that this behavior is inconsistent with an entropic lysozyme-PEG depletion interaction and suggest that an energetic lysozyme-PEG attraction is responsible. In order to independently characterize the lysozyme-PEG interactions, light scattering experiments on the same mixtures were performed to measure second and third virial coefficients. These measurements indicate that PEG induces repulsion between lysozyme molecules, contrary to the depletion prediction. Furthermore, it is shown that third virial terms must be included in the mixture's free energy in order to qualitatively capture our data. ? 2006 The American Physical Society.

Number of references: 25

Ei main heading: Phase transitions

Ei controlled terms: Light scattering - Polyethylene glycols - Mixtures - Molecular weight - Temperature - Molecules - Free energy

Uncontrolled terms: Entropic lysozyme-PEG - Virial coefficients - Phase behavior

Ei classification codes: 801.4 Physical Chemistry - 741.1 Light/Optics - 815.1.1 Organic Polymers - 802.3 Chemical Operations - 931.3 Atomic & Molecular Physics - 641.1 Thermodynamics

Treatment: Theoretical (THR)

DOI: 10.1103/PhysRevLett.96.087803

Database: Compendex

Compilation and indexing terms, ? 2006 Elsevier Inc. All rights reserved
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