Inhibition of HeLa cell DNA topoisomerase I by ATP and phosphate.
AUTOR(ES)
Low, R L
RESUMO
The relaxation activity of DNA topoisomerase I from HeLa cell nuclei is strongly inhibited by a variety of purine nucleotides in the presence but not absence of 1 mM potassium phosphate. For ATP, 3-4 mM causes nearly complete inhibition. The 2'-and 3'-AMP isomer are active as well in the presence of 1 mM phosphate, but the 5'-AMP isomer and adenosine are inert. At 3 mM ATP, the titration curve for phosphate is sigmoidal with inhibition beginning abruptly at about 0.5 mM. The negatively-supercoiled DNA isolated from an "inhibited" reaction is relaxed as well as the standard DNA template in the absence of ATP and phosphate suggesting that inhibition does not result from an alteration of the template which protects against its relaxation. Relaxation of positively-supercoiled DNA is also inhibited. Catalysis by E. coli DNA topoisomerase I and HeLa DNA topoisomerase II is not inhibited at concentrations of ATP and phosphate sufficient to cause 80-90% inhibition of HeLa type 1 enzyme.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=322018Documentos Relacionados
- Butylanilinouracil: a selective inhibitor of HeLa cell DNA synthesis and HeLa cell DNA polymerase alpha.
- Synchronization of HeLa cell cultures by inhibition of DNA polymerase alpha with aphidicolin.
- Inhibition of HeLa Cell Protein Synthesis by the Vaccinia Virion
- Breakdown of HeLa Cell DNA Mediated by Vaccinia Virus
- Transcription of adenovirus and HeLa cell genes in the presence of drugs that inhibit topoisomerase I and II function.