In "Zur Chemie des Zellkerns," Hoppe-Seyl. z. physiol. Chem. 7 (1882-83) 7-22; 10 (1886) 248-64; 22 (1896-97) 176-87, German biochemist Albrecht Kossel of Berlin showed that the substance called "nuclein" consisted of a protein component and a non-protein component. Kossel further isolated and described the non-protein component. This substance has become known as nucleic acid, which contains the genetic information found in all living cells.
Between 1885 and 1901, Kossel isolated and named the five constituent organic compounds of nucleic acid: adenine, cytosine, guanine, thymine, and uracil. Now known collectively as nucleobases, these compounds provide the molecular structure necessary in the formation of stable DNA and RNA molecules.
Kossel, "Ueber die Nucleinsäure," Arch. Anat. Physiol., Physiol. Abt., (1893) 157-64; (1894) 194-203.
J. Norman (ed) Morton's Medical Bibliography 5th ed (1991) nos. 702, 719.