A study of the molecular properties of rat-tail tendon collagen and an investigation of the structure of feather keratin

Some experimental aspects of the study of large molecules by the technique of light scattering are examined. The application of this technique to the study of rat-tail tendon collagen is then discussed. Investigations of this protein dissolved in dilute acetic acid and in concentrated urea, and a study of its transformation to "parent" gelatin lead to the suggestion of a schematic picture of the collagen molecule. A brief study of a fractionated gelatin is then described, and its molecular weight and some conclusions concerning possible molecular sizes are reported. The difficulties inherent in the investigation of gelatin solutions are examined. The final Part is concerned with a study of the structure of feather keratin by x-ray diffraction methods. The known meridional and equatorial spacings are revised and extended on the basis of measurements made on newly obtained diffraction photographs. Observed intensities are compared with those predicted for a structure which has been recently suggested