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NUCLEIC ACIDS. 179
All nucleic acids contain phosphoric acid. The relation between ph< >-
phorus and nitrogen is as 1 : 1 in the inosinic acid and as 1:5 in the guanylic
acid. In the thymus- and the salmo-nucleic acids the relation accord-
ing to Schmibdeberg is 4:14 and according to Steudel 4:15. In the
triticonucleic acid, Osborne and Harris found the relation 4:10; in the
yeast nucleic acid, Lkyene and Jacobs found it was equal to 4:15.
According to the number of bases contained in the nucleic acids
we can differentiate between the simple nucleic acid with only one base
and the complex nucleic acids with several bases. Levene and Mandel ’
have called the first (inosinic acid, guanylic acid) nucleotides or mono-
nucleotides and the last polynucleotides.
The properties and the constitution of the nucleic acids, as far as we
know them, have been determined essentially by the work of Kossel
and his pupils, by Schmiedeberg, Steudel and Levene 2
and their
collaborators.
On complete acid hydrolysis the nucleic acids are split into the three
above mentioned components, phosphoric acid, carbohydrate and bases.
The purine bases are more readily split off than the pyrimidine bases
and on careful acid hydrolysis of thymus nucleic acid, a new acid, the
ihyminic acid of Steudel and Brigl is obtained. This acid is very
similar to the thyminic acid of Kossel and Neumann a
with the barium
salt, CioH23N3P20i2Ba, and the nucleotinphosphoric acid of Schmiede-
berg. This acid differs probably from the original nucleic acid only
by the absence of purine bases. By the action of strong nitric acid in
the cold we can, according to the method suggested by Steudel, split
off the purine bases while nearly all the phosphoric acid remains in organic
combination with the carbohydrate complexes.
The hydrolyses of pentose containing nucleic acids as carried out by
Levene and Jacobs in neutral, or, if the pyrimidine complexes of the
plant nucleic acid were being studied, in ammoniacal reaction, by heating
to high temperatures in the autoclave or in sealed tubes, are of special
interest. In these cases the binding with the phosphoric acid was rup-
1
Ber. d. d. chem. Gesellsch., 41.
2
The work of Kossel and his pupils on the nucleic acids can be found in: Arch.
f. (Anat. u.) Physiol. 1892, 1893 and 1894; Sitz. Ber. d. Berl. Akad. d. Wiss., 18, 1S94;
Centralbl. f. d. med. Wiss. 1893; Ber. d. d. chem. Gesellsch., 26 and 27; Zeitschr. f.
physiol. Chem., 23 and 38; see also Neumann, Arch. f. (Anat. u.) Physiol., 1898 and 1899
Suppl.; Miescher, Hoppe-Seyler’s Med. chem. Unters., p. 441 and Arch. f. exp. Path,
u. Pliann., 37; Schmiedeberg, ibid., 37, 43, and 57; Altnian. Arch. f. (Anat. u.) Physiol.,
1889; Steudel, ibid., 42, 43, 46. 49, 50, 52, 53, 55, 56, 70, 77; Ascoli, Zeitschr. f. j
1
Chem., 28 and 31; Lev. tie, Orid., 52, 37, 38, 39, 43, 45; Levene and Mandel. ibid. 4*i.
47, 49, 50; Inouye and Kotake, ibid.. 46; Levene and Jacobs, Ber. d. d. i
Gesellsch., 42, 43, 44; with La Forge, ibid., 43 and 45.
3
Steudel and Brigl, Zeitschr. f. physiol. Chem., 70; Kossel and Neumann, ibid., 22.
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