Inhibition of the activity of DNA polymerase alpha by 2',3'-dideoxythymidine 5'-triphosphate.

2′,3′-Dideoxythymidine 5′-triphosphate was found to strongly inhibit the activity of DNA polymerase α from mouse myeloma in the presence of manganese ion as divalent cation. The extent of inhibition by 2′,3′-dideoxythymidine 5′-triphosphate increased by raising pH of the reaction. The mode of inhibition by 2′,3′-dideoxythymidine 5′-triphosphate was competitive to the substrate, 2′-deoxythymidine 5′-triphosphate. Ki of the DNA polymerase α for 2′,3′-dideoxythymidine 5′-triphosphate (0.035 μM) was much lower than Km for 2′-deoxythymidine 5′-triphosphate (1.8 μM).