Studies on nucleoproteins IV. Preparation of the deoxyribonucleoprotein and fractionation of the deoxyribonucleic acid of wheat germ

Abstract

The isolation, purification and composition of preparations of the deoxyribonucleoprotein and the deoxyribonucleic acid of wheat germ are described. The sugar constituent has been identified as 2-deoxyribose. In confirmation of previous findings, the separation of the deoxyribonucleic acid into a series of fractions showing characteristic differences in composition has been achieved by the fractional extraction of the nucleoprotein or, less effectively, of histone nucleate complexes. The distribution of 5-methylcytosine relative to that of cytosine is not uniform in the nucleic acid fractions. The nucleotide composition of the pentose nucleic acid of wheat germ has been studied; 5-methylcytosine does not appear to occur in the latter. The paper also discusses the processes of the fractionation of nucleic acids and considers some of the conclusions arising from the findings on the uneven distribution of 5-methylcytosine.