Studies on isomeric dinucleotides derived from deoxyribonucleic acid.

The occurrence of isomeric dinucleotides in the digest of deoxyribonucleic acid (DNA) with pancreatic deoxyribonuclease (DNase I) has been recently reported by Sinsheimer (1). The isomers were of the type (d)pXpY or (d)pYpX,’ the system of abbreviations being used which was suggested by Smith and Markham (2), and extended by Heppel et al. (3) and Privat de Garilhe and Laskowski (4). Although such isomers were not separable on Dowex 1 columns, they were determined by Sinsheimer (1) by the use of two consecutive degradations by enzymes: