Stimulation of DNA polymerase activity by the combination of p-hydroxymercuribenzoate and dithiothreitol

Abstract

The combination in reaction mixtures of 1 mM dithiothreitol and 1 mM p-hydroxymercuribenzoate resulted in a 10-fold stimulation in the activity of a 2.5S mouse myeloma DNA polymerase. The stimulation, first detected using poly(rA)·oligo(dT) as template-primer, was also observed with several other template-primers. In addition, a comparable stimulation was observed in the poly(rA)-directed activity of the 3.4S DNA polymerase from mouse liver, murine leukemia virus DNA polymerase and E. coli DNA polymerase I, whereas no stimulation was observed with the intracisternal A-particle DNA polymerase or the 7.9S mouse myeloma DNA polymerase. The stimulatory effect of dithiothreitol:p-hydroxymercuribenzoate appeared to be related to the mercurial portion of p-hydroxymercuribenzoate and the specific properties of dithiothreitol because HgCl 2 substituted for p-hydroxymercuribenzoate whereas p-hydroxybenzoate did not, and because other chelating reagents and compounds containing monothiols, disulfides, or adjacent dithiols did not substitute for dithiothreitol whereas the isomer, dithioerythritol, did.