Proteins: Structure, Function, and Bioinformatics

Volume 61, Issue 3 pp. 468-472

Short Communication

Anomalies in the ionic properties of serum albumin

Myer R. Salaman,

Myer R. Salaman

Department of Immunology, Imperial College School of Medicine, St. Mary's Campus, Norfolk Place, London W2 1PG, UK

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Jim Warwicker,

Corresponding Author

Jim Warwicker

[email protected]

Faculty of Life Sciences, Jackson's Mill, University of Manchester, Manchester, UK

Faculty of Life Sciences, Jackson's Mill, Sackville Street, University of Manchester, Manchester M60 1QD, UK===Search for more papers by this author

Myer R. Salaman,

Myer R. Salaman

Department of Immunology, Imperial College School of Medicine, St. Mary's Campus, Norfolk Place, London W2 1PG, UK

Search for more papers by this author

Jim Warwicker,

Corresponding Author

Jim Warwicker

[email protected]

Faculty of Life Sciences, Jackson's Mill, University of Manchester, Manchester, UK

Faculty of Life Sciences, Jackson's Mill, Sackville Street, University of Manchester, Manchester M60 1QD, UK===Search for more papers by this author

First published: 13 September 2005

https://doi.org/10.1002/prot.20628

Citations: 10

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Abstract

The documented difference in the isoionic points of native and unfolded serum albumins is revisited with computational methods. Good agreement between calculated and measured ΔpIs is found, with the molecular origin appearing to reside in a diverse set of carboxyl group titrations. Although histidine ionization plays only a minor role in bringing about the ΔpI, the identification of three histidine residues with low computed pK_as (around pH 5) suggests an explanation for the mismatch between experimentally derived group pK_as and the pI of the native protein. Computed electrostatic properties (including pI) of native serum albumins are compared with a set of 178 nonenzyme proteins. We find that the degree of interdigitation of positive and negative charges is extreme for serum albumin, and discuss the relationship to protein solubility and pH-dependent structural transitions. Proteins 2005. © 2005 Wiley-Liss, Inc.

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Volume61, Issue3

15 November 2005

Pages 468-472

Anomalies in the ionic properties of serum albumin

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Anomalies in the ionic properties of serum albumin

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