Formation and structural heat-stability of β-lactoglobulin/surfactant complexes.


Magdassi S, Vinetsky Y, Relkin P. Formation and structural heat-stability of β-lactoglobulin/surfactant complexes. Colloids Surf., BColloids and Surfaces, B: Biointerfaces. 1996;6 (6) :353 - 362.

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The binding of two model surfactants, SDS and dodecyltrimethylammonium bromide to β-lactoglobulin was studied at room temp. and the thermal stability of the resulting complexes was evaluated by differential scanning calorimetry (DSC) measurements. Binding isotherms indicated both ionic and hydrophobic interactions depending on both the charge of the protein and surfactant at different pHs and on the binding molar ratios of surfactant to the globular protein. Zeta potential measurements indicated charge neutralization of the protein, under suitable conditions, which also lead to aggregation and pptn. of the proteins. Surface tension measurements indicated similarity between the two types of oppositely charged protein-surfactant complexes and a difference between them when protein and surfactants are similarly charged. DSC measurements revealed different behavior in protein conformation in the presence of the two surfactants. The results obtained at room temp. and upon heating are discussed in terms of the nature of the surfactant/protein interactions involved in the complex formation. [on SciFinder(R)]


CAPLUS AN 1996:330723(Journal)