Differential sensitivity of low molecular weight DNA polymerase to sulfhydryl-blocking reagents

Biochim Biophys Acta. 1975 Mar 21;383(3):338-43. doi: 10.1016/0005-2787(75)90062-3.


Activity of a 2.5 S mouse myeloma DNA polymerase (termed DNA polymerase II) measured with either poly(rA) or poly(dA) as template did not require sulfhydryl-reducing reagents, but was sensitive to inhibition by p-hydroxymercuribenzoate and the sulfhydryl-alkylating reagent, N-ethylmaleimide; however, the activity was much more sensitive to inhibition by p-hydroxymercuribenzoate than by the sulfhydryl-alkylating reagent. The p-hydroxymercuribenzoate inhibition appeared to involve the mercurial portion of the p-hydroxymercuribenzoate molecule because HgCl2 was an equally effective inhibitor, while p-hydroxybenzoate had little effect upon enzyme activity. The p-hydroxymercuribenzoate inhibition was reversed by an equal concentration of the sulfhydryl-reducing reagent, dithiothreitol.

MeSH terms

  • Alkylation
  • Animals
  • Benzoates / pharmacology
  • Cell Line
  • Chlorides / pharmacology
  • DNA Nucleotidyltransferases / antagonists & inhibitors*
  • Dithiothreitol / pharmacology
  • Ethylmaleimide / pharmacology
  • Hydroxy Acids / pharmacology
  • Hydroxymercuribenzoates / pharmacology
  • Mercury / pharmacology
  • Mice
  • Multiple Myeloma / enzymology*
  • Oxidation-Reduction
  • Structure-Activity Relationship
  • Sulfhydryl Reagents / pharmacology*


  • Benzoates
  • Chlorides
  • Hydroxy Acids
  • Hydroxymercuribenzoates
  • Sulfhydryl Reagents
  • DNA Nucleotidyltransferases
  • Mercury
  • Ethylmaleimide
  • Dithiothreitol