Biochemical Studies during the Development of the Chick Embryo

Part V Determination of Base Composition (Deoxyriboside Level) of Some Nucleic Acids and Acid Insoluble Fractions Prepared from the Chick Embryo, and Those Changes of Deoxyribosyl Compounds in Acid

Abstract

In order to determine the base composition of deoxyribonucleic acid or related compounds under the presence of RNA and the related compounds or in acid insoluble fractions, the present method was devised. This method consists of the enzymatic hydrolysis, separation of hydrolysates by paper chromatography and paper electrophoresis, and the estimation of the fraction with L. leichmannii method. This method permits the determination of deoxy-riboside composition of the smaller amounts of DNA or the related compounds with relatively high accuracy even under the presence of any other compounds.
By this method, the ratio of each deoxyriboside in the enzyme hydrolysate of acid insoluble fractions prepared from the 3 to 19 day old embryos was determined. Among the major deoxyribosides, the contents of deoxyguanosine and of deoxycytidine were nearly constant during the development of the embryo, whereas, those of thymidine and of deoxyadenosine appear to undergo a change slightly at the periods from 10 to 15 days. It is interesting that the periods coincided with the time of the most marked synthesis of DNA, that of most significant changes of deoxyribosyl compounds in acid soluble fraction and that of the most excellent growth of the embryo.