| Abstract: | The optical rotatory dispersion (ORD), and to a lesser extent the circular dichroism (CD) of the proteins tropomyosin and myosin have been extensively studied. The effect of aging and of certain reagents on these optical properties, relating to helical contents, were observed. As expected, spectra typical of right-handed, α-helices were found, with helical contents of 60–65% for myosin and 97–100% for tropomyosin. Studies were made to find which aqueous salt solutions would permit rotation observations in the far ultraviolet and also dissolve these proteins. The presence or absence of sulfhydryl groups (SH) were found to have no effect on helicity, and it is suggested that both proteins have an identical helical portion of 40%. |
