摘要：

An apparatus first described in 1961 for the measurement of circular dichroism down to 220 m has been improved and its range extended down to 185 m . Some examples are given in the field of dienes, conjugated ketones, and aromatic chromophores. A more extensive study of protein structures was developed with the following results: (a) helical polypeptides show a complex dichroism in the far ultraviolet with three components (192 m , 204 m , 225 m ), characteristic of the helical array of peptide groups; (b) human serum albumin shows a very similar curve of dichroism and is 60% helical; (c) urea denaturation, as judged by dichroism, is a reversible phenomenon; (d) a solvent such as chloroethanol increases the helical content of human serum albumin and clupein and has only a very small action on poly-L-glutamic acid; (e) the rupture of S S bonds in human serum albumin favors the attack of denaturing agents such as urea; (f) detergents help to maintain the rigid structure of human serum albumin after the rupture of S S bonds.

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