Structural Stability of Globulins

Application of differential scanning calorimetry (DSC) and the susceptibility of amaranth globulins (A-G) to α-chymotrypsin gave a quantitative estimation of protein denaturation in solid state. To compare effects of size and crystal structure, A-G, quinoa globulins (Q-G), and bovine γ-globulins (γ-G) were examined at similar conditions for the extent of denaturation. A-G and Q-G showed similar data, but γ-G exhibited maximal conformational changes. The larger percentage of denaturation in globulins that is associated with enthalpy and the number of ruptured hydrogen bonds correspond to the smaller crystallinity determined by X-ray diffraction and disappearance of the α-helix in Fourier transform-infrared spectra. Keywords: Amaranth; quinoa; calorimetry; denaturation; spectroscopy