ABSTRACT
Atlow concentrations, dimethyl sulfoxide (DMSO), stimulated the avian myeloblastosis virus reverse transcriptase activity. About 40 percent stimulation was obtained in the presence of 5 percent (v/v) DMSO, using activated DNA and polyriboadenylic acid (poly(rA)) as templates, and Mg2+ as divalent cation. A similar stimulation by DMSO was observed with Mn2+ for the poly(rA)-dependent reverse transcriptase activity. DMSO at concentrations higher than 15 percent inhibited the reverse transcriptase reactions, independent of the template-primers used. An exception was detected with the 2'-fluoro analog of poly(rA) as template, where an activation of 100 percent was found in the presence of 20 percent DMSO. The stimulation caused by DMSO could be due to a reduction of the apparent Km value for poly(rA) from 9.1 to 3.3 µg/ml
Subject(s)
Animals , Dimethyl Sulfoxide/pharmacology , RNA-Directed DNA Polymerase/metabolism , Avian Myeloblastosis Virus/enzymologyABSTRACT
Extracts from higher plants were evaluated for inhibitory activity against avian myeloblastosis virus reverse transcriptase. The assay may serve as a useful prescreen for potential anti-HIV bioactives
Subject(s)
Antiviral Agents/pharmacology , Plant Extracts/pharmacology , RNA-Directed DNA Polymerase/antagonists & inhibitors , Drug Evaluation, Preclinical/methods , HIV/drug effects , Puerto Rico , Avian Myeloblastosis Virus/enzymologyABSTRACT
Poly (2'-O-methylcytidylic acid) is recognized as a template in reactions catalyzed by RNA-dependent DNA polymerases in the presence of Mn2+ as divalent cation. We report that kinetic data obtained for dGTP and template under optimal experimental conditions in the reaction catalyzed by reverse transcriptase showed some similarities between the poly (2'-O-methylcytidylic acid)Mn2+ and polyribocytidylic acid/Mg2+ systems. The reaction was inhibited by the action of N-ethylmaleimide and novobiocin, and to a lesser extent by ethidium bromide and tetramethyl ethidium bromide
Subject(s)
Avian Myeloblastosis Virus/enzymology , Guanosine Triphosphate/metabolism , Poly C/metabolism , RNA-Directed DNA Polymerase/metabolism , Binding Sites , Magnesium/metabolism , Manganese/metabolismABSTRACT
Poly (2'-O-methyladenylic acid), poly (Am), is recognized as template in the reaction catalyzed by avian myeloblastosis virus, AMV, reverse transcriptase better in the presence of Mn than Mg as divalent cation. An apparent KM value of 2.5 x 10 M in relation to TTP and an inhibition of the reaction at poly (Am concentration higher than 5 microng/ml have been observed. Ethidium bromide, EtBr, tetramethyl ethidium bromide, TMEtBr, dideoxy TTP, and novobiocin are inhibitors of the poly (Am)-directed reverse transcriptase reaction in the presence of Mn