Nucleic acids : their chemical properties and physiological conduct / by Walter Jones.

  • Jones, Walter, 1865-1935
Date:
1920
Catalogue details

Licence: In copyright

Credit: Nucleic acids : their chemical properties and physiological conduct / by Walter Jones. Source: Wellcome Collection.

    20/168 (page 8)
    /3-N ucieoproteins. The first member of this group was prepared by Hammarsten from the pancreas [1894]. Finely ground glands were suspended in water and the mixture quickly heated to boiling. The pale yellow trans- parent fluid was filtered from the bulky dark brown coagulum and treated with acetic acid, when the /Tnucleoprotein was thrown out as a white flocculent precipitate. The difference between this procedure and that employed in the preparation of a-nucleoprotein is notable. Most of the glandular constituents are thrown down with the heat coagulum and the rest are left in solution, when the nucleoprotein is precipitated with acetic acid. Upon hydrolysis of /3-nucleoprotein, Hammarsten obtained a re- ducing pentose and but one of the alloxuric bases, viz. guanine: the substance is thus sharply distinguished from <%-nucleoprotein. Similar /3-nucleoproteins have been obtained from the mammary gland (Odenius [1900]), the spleen (Jones and Rowntree [1908]), and the liver (Levene and Mandel [1908]), and the wide occurrence of pen- tose in animal tissues (Rlumenthal [1897], Bang [1897], Wohlgemuth [1904]) is almost certainly to be ascribed to the /3-nucleoprotein which they contain. But it should not be understood that /3-nucleoproteins are protein salts of nucleic acid, nor that they are constituents of cell nuclei. When the protein is removed from them there remains a substance called guanylic acid which yields phosphoric acid and guanine, but is not a nucleic acid in the narrow sense of the term as will be explained in Chapter III. To regard a-nucleoproteins and nucleins as protein salts of nucleic acid is not to detract from the important writings of those who formerly looked upon the matter in a different light (Pekelharing [1895]). Kos- sel kept alive a keen interest in nucleins so long as he was compelled to work with them ; but he was quick enough to abandon nuclein with its protein complexity for the “ prosthetic group/’ which could be made to yield definite results by the application of the methods of organic chemistry.