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Molecular studies of a mammalian DNA kinase

Whole cell extracts from fresh calf thymus glands were subjected to Polymin P fractionation and Q Sepharose chromatography. Three peaks of DNA kinase activity, designated SNQI, SNQII and SNQIII, were found in the supernatant fraction. Studies of SNQI have revealed an estimated molecular mass of 50-90 kDa by Superose 12 chromatography, and activity gel analysis following SDS-PAGE identified an active polypeptide of approximately 55 kDa. This enzyme preparation, purified 10,000-fold, phosphorylated 5$ sp prime$-OH-terminated oligodeoxyribonucleotides and double stranded DNA, yet was inactive on an oligoriboadenosine ladder. SNQI functions optimally at an acidic pH in 10 mM MgCl$ sb2$, but is inhibited by both sulfate and pyrophosphate anions. The estimated K$ sb{ rm M}$ values were 2.3 $ mu$M for the oligonucleotide substrate and 11.8 $ mu$M for ATP. Similar to an enzymatic activity previously isolated from rat liver, SNQI is the first bovine preparation to display both 5$ sp prime$ kinase and 3$ sp prime$ phosphatase activities. / Partial purification and characterization of SNQII revealed similarities to SNQI, such as an acidic pH optimum and the presence of 3$ sp prime$ phosphatase activity. DNA kinase activity was also demonstrated in two mammalian cell lines.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.23938
Date January 1996
CreatorsSlack, Carolyn
ContributorsLasko, Dana D. (advisor)
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Science (Department of Biology.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 001507984, proquestno: MM12273, Theses scanned by UMI/ProQuest.

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