Synthesis of <i>N</i>‐Acetylated Deoxyribonucleoside 5′‐Triphosphates and their Utilization in Enzymatic Formation of Single‐Stranded Polydeoxyribonucleotides

Abstract

The N ‐acetylated deoxyadenosine and deoxyguanosine 5′‐triphosphates (dA Ac TP and dG Ac TP) have been synthesized and found competent as substrates for enzymatic chain lengthening of polydeoxyribonucleotides without concomitant loss of the acetyl group. The enzyme used was terminal deoxyribonucleotidyltransferase. The addition of dG Ac units proceeds without aggregation that self‐limits addition of nonacetylated dG units. The resulting polymer 3′‐ended with dG Ac units is an efficient initiator for subsequent chain lengthening. Hydrogen bonding is not destroyed by N ‐acetylation of the dA‐dT Watson‐Crick pair, although it is considerably weakened. As a practical result of this, a polymer 3′‐ended with dA Ac units is a much more efficient initiator for enzymatic chain lengthening by dT units than is a corresponding polymer with dA units. Venom phosphodiesterase does not hydrolyze a polymer 3′‐ended with dA Ac units.