The composition of nucleic acids; the guanine and thymine content of nucleic acids isolated from normal tissues and animal tumours.

D L Woodhouse

doi:10.1038/bjc.1949.54

Abstract

The Composition of Nucleic Acids: The Guanine and Thymine Content of Nucleic Acids Isolated from Normal Tissues and Animal Tumours

Highlights

The complete removal of the protein from the nucleic acid requires special attention, in preparations made from liver and from spleen, and experience showed that the process of dissociation by the chloroform-octyl alcohol method of Sevag, Lackman and Smollens (1938) must be repeated many times to remove the protein completely
Mirsky (1943), described the ratio of total purines to pyrimidine in deoxy-pentose nucleic acid as "equimolecular" in specimens obtained from animal tissues and from wheat germ
This conclusion was based partly on experimental evidence, which suggested that the ratio of purines to pyrimidines in nucleic acids could be calculated by comparing the intensity of colour obtained by the Dische diphenylamine reaction (Dische, 1930) with the total nucleic acid as indicated by the phosphorus content

Summary

METHODS

Analyses for phosphorus content, deoxypentose, thymine and guanine were carried out on these samples, using the following methods of colorimetric determination in which a Spekker absorptiometer was employed. In final volume of 10 ml.) is similar in type, but the intensity of colour obtained from a known weight of pentose is greater than that produced from an equivalent amount of deoxyribose nucleic acid if this is calculated assuming the conventional tetra-nucleotide structure. The following tests were made during the course of various experiments undertaken to investigate the conditions necessary for the determination of the guanine content of nucleic acid and nucleotides. The guanine could be determined quantitatively in a solution of a pure sample of guanylic acid after hydrolysing with.

Findings

Nucleic acid A

DISCUSSION