Effect of Solvent and Temperature on Secondary and Tertiary Structure of Zein by Circular Dichroism

Abstract

ABSTRACT Circular dichroism studies were performed on zein to determine how the secondary and tertiary structure changes with different solvents, temperatures, or pH. Alcoholic solvent type and common denaturants such as SDS and low amounts of urea had little effect on the secondary structure of zein. Utilization of dimethylformamide or acetic acid as solvent gave changes in tertiary structure. Solutions of zein in 8 M urea produced solutions with large changes in tertiary structure. The dissolution of zein in 50 m M sodium hydroxide produces a zein with large changes in secondary and tertiary structure and little loss in primary structure. Increasing the temperature of zein to 70°C in 80% ethanol‐water gave reversible changes in the primary structure (20% reduction in absolute magnitude of [θ]λ at 208 and 222 nm) and tertiary structure (40% reduction in absolute magnitude of [θ]λ at 268 nm).