Food Chemical Study of Soybean Proteins

Part VIII. Conformational change of 11S component of soybean proteins in alkali

Abstract

The comformational change of the 11S component of soybean proteins in alkali was measured by ultraviolet difference spectra, optical rotatory dispersion and circular dichroism. The abnormal tyrosyl residues of the 11S component were classified into two types. The first type was normalized when the pH was increased above 11.0, but the second type could not be exposed at pH 12.70. The behavior of the a₀ value in Moffitt-Yang equation suggested that the secondary and tertiary structure of the 11S component were stable, partially. From the cotton effect and CD spectra, it was found that the partially stable secondary structure was a β-structure.