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.

    19/168 (page 7)
    Leuco-nucleo-histone Protein Nucleic Acid In a subsequent communication Lilienfeld [1892, 2] reconsidered his experimental findings and changed his nomenclature, but the implication remained that in thymus-nucleoprotein the nucleic acid is in combination with two different proteins. If such a finding could be sustained a particular meaning would be given to the expres- sion “ nucleoprotein ”; but from the unanimous testimony on this point of Malengreau [1900], Huiskamp [1901]: [1903], and Bang [1904] we are to conclude that Lilienfeld was dealing with a mixture of two or more substances, and we are left with no more information than that proteins and histones alike form combinations with nucleic acid which differ from one another in the relative ease with which they can be precipitated by various reagents. Nucleo-histone came into physiological chemistry on a high wave of enthusiasm which has served for its preservation for many years ; but the recent work of Steudel [1913], [1914] would seem to make a final disposal of the substance. He finds that specimens of nucleo- histone have a composition that depends entirely upon the method used in their preparation. After a careful examination of a mass of badly tangled evidence upon the subject one is likely to conclude that a-nucleoprotein con- sists of various salts of protein with nucleic acid in which the protein is in excess ; that when the substances are submitted to the action of pepsin-hydrochloric acid part of the protein is digested away leaving a mixture of more acid salts indefinitely called nuclein, and more re- sistant to the action of the ferment. The terms nucleoprotein, nuclein and nucleic acid therefore express a relation which means little more than that conveyed by the terms basic lead acetate, lead acetate and acetic acid. At least this is the greatest concession that can be made, for in reality “ nucleoprotein ” means rather “ a method of preparation ” than a chemical substance. A specimen was actually looked upon as identical with trypsin (Hammarsten [1894]) : all are probably contam- inated with glucothionic acid (Levene and Mandel [1906, 1]).