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Ultra-violet Absorption of Genuine and Hydrolysed Protein


ACCORDING to the classical theory of protein structure, the carboxyl and amino groups found after hydrolytic splitting of a protein come from –CO–NH– bonds. According to the cyclol hypothesis (Wrinch1), however, the free carboxyl and amino groups must be formed, during the splitting, from bonds of the structure >C(OH)–N<. The classical theory would predict on hydrolysis no great change in the absorption spectrum below 2400 A. because the CO groups of the amino acids and of the peptide bonds both are strongly absorbing in this region2. On the other hand, the cyclol hypothesis would predict a greatly increased absorption because of the formation of new CO groups.

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  1. Wrinch, D. M., NATURE, 139, 798, 972 (1937).

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  2. Cf. Magill, M. A., Steiger, R. E., and Allen, A. J., Biochem. J., 31, 188 (1936).

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HAUROWITZ, F., ASTRUP, T. Ultra-violet Absorption of Genuine and Hydrolysed Protein. Nature 143, 118–119 (1939).

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