Über Oligonucleotide aus Thymo-nucleinsäure. Nucleinsäuren III

Abstract

Calf thymus glands were boiled 5 min. in 0.5% acetic acid, stored under toluene in the ice box 5-14 days and ground. From 10 kg. of this mixture, 1400 g. crude product containing 2.99% P, were prepared by the method of Feulgen (Hoppe-Seyler''s Zeitschr. physiol. Chem., 238: 105, 1936). The oligonucleotides were prepared by stirring 300 g. of the crude product with 600 ml. boiling H2O, cooling the mixture to 37[degree], adding 25 g. dried pig pancreas powder dissolved in 250 ml. H2O, and incubating the mixture 7 hrs. at 37[degree], etc. The mixture was centrifugalized, the supernatant soln. coned, to 220 ml. in vacuo, treated with 20 g. NaOH in 20 ml. H2O, and the Na salt of the oligonucleotides precipitated by adding 650 ml. etha-nol. The Mg salt of the oligonucleotide was also prepared, and contained the theoretical amts. of purine, guanine and adenine. To show the homogeneity of the substance, the oligonucleotide prepn. was subjected to fractional dialysis, and 8 fractions obtained. The dialysis coefficient, y, for fractions II-VI, was 1.57-10"3 -1.55-10"3, and the particle size, 1120-1160. The agreement for the different fractions of the dialysis coefficients, of the particle size and the composition of the substance, CsoKiTOiisNjsPiMgz, led to the conclusion that desribotetranucleotide was formed by the action of polynucleotidase on thymonucleic acid. The optical rotation of the substance was (a)B20= +29.9[degree].