Optical rotatory dispersion of egg proteins. I. Ovalbumin, conalbumin, ovomucoid, and lysozyme

Abstract

Abstract Optical rotatory dispersions (ORD) of ovalbumin, conalbumin, ovomucoid, and lysozyme (muramidase) were measured in aqueous solution over a wavelength range of 195–600 mμ. The dispersion curves obeyed a one‐term Drude equation above 300 mμ. The strong Cotton effects in the ultraviolet showed peaks and troughs at about the same wavelength for all four proteins, but the crossover point for the 225 mμ Cotton effect for ovomucoid was appreciably lower than for the other proteins. Helical contents calculated by using the Moffitt equation, the trough value of the 225 mμ Cotton effect, and the expressions for helical content recently proposed by Schechter and Blout ranged from 5 to 34%. Except for ovomucoid, the trough value of the 225 mμ Cotton effect gave the lowest helical content.