On nucleic acids

Abstract

In recent years, several substances have been obtained which resemble one another in the fact that all of them contain in their molecules phosphoric acid and a sugar, but which differ one from another in the number and in the character of the nitrogenous radicals contained in their molecules. To this group of substances belong: (1) glucophosphoric acid; (2) inosinic acid and guanylic acid; (3) yeast nucleic and triticonucleic acid; and (4) thymonucleic acid.

All these substances may be classified as nucleic acids:

1. The first substance is a glucophosphoric acid proper.

2. Inosinic and guanylic acids are monopurin-glucophosphoric acids. Each of them contains in its molecule only one purin base besides the glucophosphoric acid.

3. Yeast and triticonucleic acids each contains two purin and one pyrimidin radical in its molecule and may be regarded as dipurin-monopyrimidin-glycophosphoric acid.

4. Finally, thymonucleic acid is a dipurin-dipyrimidin-gluco-phosphoric acid.

Conclusions as to the nature and existence of the monopurin-glucophosphoric acid have passed through several phases during the past year. Last summer a paper by v. Furtli and Jerusalem appeared in which the existence of the substance was denied. However, within a short time, work done by Steudel, by Jones and by ourselves has not only established the existence of the substance, but also has shown that its occurrence is more general in animal organs than has hitherto been conceded, In fact, with the acceptance of this discovery, some investigators are inclined to regard thymonucleic acid as simply a mixture of different monopurin-glucophosphoric acids.

However, it is possible that all nucleic acids resemble one another in the order in which the components are linked together. There is support for the assumption that the carbohydrate is joined to the phosphoric acid and the base to the carbohydrate in a glucoside form.