Influence of surfactants on the conformation of β‐lactoglobulin B using circular dichroism

Abstract

SynopsisThe effect of several surfactants on the secondary structure of bovine 0-lactoglobulin B was determined from the circular dichroism spectra. The spectra were measured a t several concentrations of surfactant ranging from 1 mg/mL to the critical micelle concentration. The surfactants studied were sodium dodecyl, decyl, and octyl sulfate, sodium dodecyl sarcosinate, dodecyltrimethylammonium bromide. The data were analyzed using the method of Chen et al. [Biochemistry (1974) 13,3350-33591 to determine the percentage of a-helix, &sheet, and unordered form a t each surfactant concentration. In every case, an increase in structured form and a 20-25% decrease in the amount of unordered form was noted when the surfactant concentration reached the critical micelle concentration. However, the relative amounts of the two structured forms present depend on the surfactant used. The profile of the secondary structure of the protein also varied from surfactant to surfactant as the protein was titrated, probably reflecting the delicate balance between ionic and nonionic forces that governs the secondary structure of 0-lactoglobulin and most other globular proteins in aqueous solution.

Ion-selective electrodes for octyl and decyl sulfate surfactants

“…Our previous circular dichroism studies (10) have shown that the addition of both sodium octyl and decyl sulfate abruptly increases the amount of a-helical and 8-structure of 8-lactoglobulin at the expense of the unordered form in aqueous solution at 22 + 1 °C. Therefore, studies were performed under similar conditions (10) with aqueous solutions of 8-lactoglobulin AB using the electrodes to determine if the binding behavior paralleled the conformational changes. The results obtained resembled the titration curves shown in Figure 4 for the titration of PVP.…”

“…1978, 253, 4971-4979. (10) Dryhurst, G. "Electrochemistry of Biological Molecules"; Academic Press: New York, 1977; Chapter 7.…”

Adsorption of β‐Lactoglobulin variants A and B to the air–water interface

“…Bovine ␤-lactoglobulin (␤-lg) is the major protein in whey (Wong et al, 1996). ␤-Lg has been highly characterized over recent years in all aspects of its behaviour from structural and biochemical properties (Damon & Kresheck, 1982;Papiz et al, 1986;Huang et al, 1994;Wong et al, 1996;Manderson et al, 1998;Renard et al, 1998) to functional properties such as lipid binding (Jones & Wilkinson, 1976;Damon & Kresheck, 1982;Coke et al, 1990;Clark et al, 1992), adsorption (Waniska & Kinsella, 1985;Luey et al, 1991) foaming (Coke et al, 1990), gelation (Foegeding et al, 1992) and emulsification (Shimizu et al, 1985;Das & Kinsella, 1989;Cornec et al, 1998). It has two main genetic variants; ␤-lg A (mol.…”

Enhancing storage stability of emulsions by binding detergents with soy protein isolate and its hydrolysates

“…ES of emulsions increased with increasing protein concentration. SDS can change the conformation of proteins (8,10,24) and stabilize the helix of proteins by forming a hydrophobic shield around peptide bonds (12). It was thought that S 0 may be a static factor and flexibility a dynamic factor in the surface properties of proteins (15).…”

“…Protein ingredients in cosmetics can enhance those detergent functions and protect skin from the undesirable effects of detergents. Detergents can modify protein conformation and increase protein dispersability and surface hydrophobicity (8)(9)(10)(11). Teglia et al (6) demonstrated the cosmetic properties of protein hydrolysates-sodium lauryl sulfate complex (6).…”