title: Specific inhibition of DNA polymerase-associated RNase H by DNA.
abstract: The RNase H activity associated with several RNA-directed DNA polymerases is inhibited by the addition of DNA, in contrast to RNase H activity from enzymes devoid of polymerizing activity. Kinetic investigations of the inhibitory effect of DNA, using purified Rauscher leukemia virus DNA polymerase as a test enzyme, revealed that the addition of DNA to an ongoing RNase H reaction causes an immediate cessation of RNase H activity. Concomitant initiation of DNA synthesis by inhibitory DNA can occur, provided that appropriate substrate and primer is available. Thus, in addition to providing a simple test for the distinction between polymerase-associated and polymerase-independent RNase H activity, this study strongly supports the concepts that (i) RNase H activity expressed by several mammalian oncoviral reverse transcriptases is an integral part of that molecule, and (ii) that the catalytic site of RNase H activity is also involuved in template-primer binding.
mesh_terms: D004247:DNA / Q000494:pharmacology; D004279:DNA, Viral / Q000096:biosynthesis; D011119:Polynucleotides / Q000494:pharmacology; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D011925:Rauscher Virus / Q000201:enzymology* / Q000378:metabolism; D012260:Ribonucleases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013698:Templates, Genetic
chemical_list: D004279:DNA, Viral; D011119:Polynucleotides; D004247:DNA; D012194:RNA-Directed DNA Polymerase; D012260:Ribonucleases