λ DNA-Fragmenting Actions of Ascorbic Acid and Triose Reductone in the Presence of Cu²⁺

Lambda DNA-fragmenting actions of ascorbic acid (AsA) and triose reductone (TR) in the presence of Cu2+ were studied. The mixture of AsA or TR and Cu2+ caused a marked fragmentation of IDNA (3.2x107 daltons) within the first 1 min of reaction. Further incubation resulted in accumulation of the most abundant species of fragmented ADNA having a molecular weight of 1.3 x 105 daltons. The mixture of AsA or TR and Cu2+ fragmented calf thymus DNA to produce the fragmented DNA of which 5'-0H terminal groups have a mixture of free OH groups and phosphodiester linkage. The mixture of AsA or TR and Cu2+ was also found to fragment ADNA to produce dCMP predominantly as 5'-OH terminal nucleotides.