Towards control of aggregational behaviour of a-Lactalbumin at acidic pH

Towards control of aggregational behaviour of a-Lactalbumin at acidic pH
Engineering Village 2
? 2006 Elsevier Inc
Accession number: 062910012013

Title: Towards control of aggregational behaviour of a-Lactalbumin at acidic pH

Authors: Pedersen, Jane B.; Fojan, Peter; Sorensen, John; Petersen, Steffen B.

Serial title: Journal of Fluorescence

Abbreviated serial title: J Fluoresc

Volume: v 16

Issue: n 4

Issue date: July 2006

Publication year: 2006

Pages: p 611-621

Language: English

ISSN: 1053-0509


Document type: Journal article (JA)

Publisher: Springer Science and Business Media Deutschland GmbH, Berlin, 14197, Germany

Abstract: a-Lactalbumin (a-La) undergoes considerable structural changes upon loss of bound Ca2+ at acidic pH, leaving a-La in a molten globule structure. Using fluorescence the present work provides more insight into the structural transition of a-La at acidic pH leading to protein aggregation, most likely caused by a combination of hydrophobic and electrostatic interactions. The rate of aggregation is determined by the protein concentration and temperature applied. Availability of Ca2+ stabilises the protein, and thus prevent aggregation at pH values as low as pH 2.9. In contrast, presence of Cu2+ induces a destabilisation of the protein, which can be explained by a binding to the Zn2+ binding site in a-La, possibly resulting in structural alterations of the protein. In general, presence of anions destabilise a-La at pH values below pI, with SO4 2- exhibiting the strongest effect on the protein stability, thus correlating well with the Hofmeister series. At more acidic pH values far from pI, a-La becomes more stable towards ion induced aggregation, since higher ion activity is required to efficiently screen the charges on the protein surface. The results presented in this paper provide detailed knowledge on the external parameters leading to aggregation of a-La at acidic pH, thus permitting rational design of the aggregation process.

Number of references: 27

Ei main heading: Proteins

Ei controlled terms: Agglomeration - pH effects - Acidity - Fluorescence - Hydrophobicity - Electrostatics

Uncontrolled terms: a-Lactalbumin - Protein aggregation - Acrylamide quenching - Fluorescence spectroscopy - Confocal microscopy

Ei classification codes: 804.1 Organic Compounds - 802.3 Chemical Operations - 801.1 Chemistry, General - 741.1 Light/Optics - 701.1 Electricity: Basic Concepts & Phenomena

Treatment: Experimental (EXP)

DOI: 10.1007/s10895-006-0088-6

Database: Compendex

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