Separation of topoisomerase I activity from the regulatory subunit of type II cyclic adenosine monophosphate-dependent protein kinase.
The cAMP-containing phosphoform of the regulatory subunit (RII) of type II cAMP-dependent protein kinase from rat liver has been reported to have intrinsic DNA topoisomerase I activity. We found that highly purified RII preparations from eight different sources, including rat liver, contained no detectable topoisomerase I activity. Topoisomerase I exhibited an overlapping peak of activity with RII when rat liver extracts were fractionated by diethylaminoethyl-cellulose chromatography. Topoisomerase I activity was separated from RII by subsequent cAMP affinity chromatography. The results indicate that the regulatory subunit of cAMP-dependent protein kinase does not contain intrinsic topoisomerase I activity.
Shabb
J B
JB
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Granner
D K
DK
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D010584:Bacteriophage phi X 174 / Q000235:genetics; D002417:Cattle; D002848:Chromatography, DEAE-Cellulose; D000242:Cyclic AMP / Q000494:pharmacology*; D004264:DNA Topoisomerases, Type I / Q000302:isolation & purification*; D004278:DNA, Superhelical / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D000882:Haplorhini; D008099:Liver / Q000201:enzymology*; D008168:Lung / Q000201:enzymology; D008297:Male; D009206:Myocardium / Q000201:enzymology; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification*; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine
D004278:DNA, Superhelical; D004279:DNA, Viral; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D011494:Protein Kinases; D004264:DNA Topoisomerases, Type I