Biomaterial Database

Differential effects of captan on DNA polymerase and ribonuclease H activities of avian myeloblastosis virus reverse transcriptase. 1986

M J Freeman-Wittig, and M Vinocour, and R A Lewis

Captan was used as an inhibitor of avian myeloblastosis virus reverse transcriptase to study the polymerase and RNase H catalytic activities. With purified enzyme, RNase H activity was 10-fold more sensitive to captan than was either the DNA-dependent or RNA-dependent DNA polymerase activity. Inhibition of the RNA-dependent polymerase activity could be prevented by dTTP. Conversely, inhibition of this polymerase activity was enhanced by template/primer. The calculated KdTTP of the uninhibited reaction was 5.6 microM. Kinetic studies allow for the proposition of a model for the interaction of captan with the polymerase active center. RNase H activity showed a sigmoidal relationship between activity and substrate concentration. Nuclease activity decreased in Vmax with no change in the Hill coefficient in the presence of captan. Addition of dithiothreitol to the incubation cocktail prevented inhibition by captan of both RNA-dependent polymerase and RNase H activities, suggesting that the (trichloromethyl)thio moiety of captan is involved in the inhibitory action. Captan inhibition suggests the presence of essential amino residues in both polymerase and RNase H active centers.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009189	Avian Myeloblastosis Virus	A species of ALPHARETROVIRUS causing anemia in fowl.	Myeloblastosis Virus, Avian,Avian Myeloblastosis Viruses,Myeloblastosis Viruses, Avian,Virus, Avian Myeloblastosis,Viruses, Avian Myeloblastosis
D002215	Captan	One of the phthalimide fungicides.	N-Trichloromethylthio-4-cyclohexane-1,2-dicarboximide,Vancide 89,N Trichloromethylthio 4 cyclohexane 1,2 dicarboximide
D004229	Dithiothreitol	A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.	Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
D004259	DNA-Directed DNA Polymerase	DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.	DNA Polymerase,DNA Polymerases,DNA-Dependent DNA Polymerases,DNA Polymerase N3,DNA Dependent DNA Polymerases,DNA Directed DNA Polymerase,DNA Polymerase, DNA-Directed,DNA Polymerases, DNA-Dependent,Polymerase N3, DNA,Polymerase, DNA,Polymerase, DNA-Directed DNA,Polymerases, DNA,Polymerases, DNA-Dependent DNA
D004722	Endoribonucleases	A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.	Endoribonuclease
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005033	Ethylmaleimide	A sulfhydryl reagent that is widely used in experimental biochemical studies.	N-Ethylmaleimide,N Ethylmaleimide
D001354	Avian Leukosis Virus	The type species of ALPHARETROVIRUS producing latent or manifest lymphoid leukosis in fowl.	Leukosis Virus, Avian,Lymphomatosis Virus, Avian,Rous-Associated Virus,Avian Leukosis Viruses,Avian Lymphomatosis Virus,Avian Lymphomatosis Viruses,Leukosis Viruses, Avian,Lymphomatosis Viruses, Avian,Rous Associated Virus,Virus, Avian Leukosis,Virus, Avian Lymphomatosis,Virus, Rous-Associated,Viruses, Avian Leukosis,Viruses, Avian Lymphomatosis
D012194	RNA-Directed DNA Polymerase	An enzyme that synthesizes DNA on an RNA template. It is encoded by the pol gene of retroviruses and by certain retrovirus-like elements. EC 2.7.7.49.	DNA Polymerase, RNA-Directed,RNA-Dependent DNA Polymerase,Reverse Transcriptase,RNA Transcriptase,Revertase,DNA Polymerase, RNA Directed,DNA Polymerase, RNA-Dependent,RNA Dependent DNA Polymerase,RNA Directed DNA Polymerase