Further studies on rotatory dispersion and structure of globular proteins

New and formerly obtained data on the optical rotatory dispersion of globular proteins are tabulated, classified, and correlated to certain structural features of these proteins. According to their rotatory dispersion behavior, all globular proteins are classified into three groups: (1) those possessing high dispersion constants of 245–290 mμ, (2) those with low dispersion constants of 220–245 mμ, and (3) the globular proteins which, when in the native state, have abnormally low dispersion constants below 220 mμ. It was found that all thus far studied globular proteins showed simple dispersion, i.e. followed the one‐term DRUDE rule, when the rotatory power of their aqueous solutions was observed with light of the wave lengths between 365–700 mμ. Also it was found that the α‐helical globular proteins possessing high dispersion constants exhibited complex dispersion with wave lengths shorter than 365 mμ. It was concluded that the 3rd class proteins with the abnormally low dispersion constants are non‐helical, and that in these cases one has to deal with other specific conformations that cannot be identified with either α‐helix or random chain. The macromolecular changes and conformation of some serum globulins were considered in some detail in this study.