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

✍ Scribed by Amy Jo Hillquist Damon; Gordon C. Kresheck

• Publisher: Wiley (John Wiley & Sons)
• Year: 1982
• Tongue: English
• Weight: 711 KB
• Volume: 21
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360210504

✦ Synopsis

Abstract

The effect of several surfactants on the secondary structure of bovine β‐lactoglobulin B was determined from the circular dichroism spectra. The spectra were measured at 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, 3350–3359] to determine the percentage of α‐helix, β‐sheet, and unordered form at 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 β‐lactoglobulin and most other globular proteins in aqueous solution.