Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1977-5-27
pubmed:abstractText
The Novikoff hepatoma DNA polymerase-beta sediments as a 7.3S form in crude extracts but during purification sediments as a 4.1S form (after diethylaminoethyl-Sephadex chromatography) or as a 3.3S form (after DNA-cellulose chromatography). If 0.25 M ammonium sulfate or 0.5 M NaCl is included in the sucrose gradients, the 7.3S form sediments at 3.3 S; after removal of the salt, it sediments again at 7.3 S, indicating the reversibility of the aggregation phenomenon. By careful adjustment of ionic strength in the gradient, four distinct and reproducible forms of the enzyme sedimenting at 7.3, 5.8, 4.1, and 3.3 S can be generated. The isoelectric point of the DNA polymerase also changes during purification; the 7.3S form has a pI of 7.5, while the 4.1S form isoelectrically focuses at a pH of 8.5. During DNA-cellulose chromatography, the Novikoff beta-polymerase is separated from a stimulatory factor designated as Novikoff factor IV. Factor IV is a protein as shown by its sensitivity to protease and resistance to nucleases. It is responsible for converting the 3.3S enzyme to the 4.1S form since the 3.3S homogeneous DNA polymerase-beta sediments at 4.1 S in the presence of factor IV. Factor IV confers stability to the polymerase in low ionic strength buffers as well as stability to heat denaturation. Factor IV has the ability to increase the activity of the 3.3S homogeneous polymerase by about fourfold.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1512-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Novikoff hepatoma deoxyribonucleic acid polymerase. Identification of a stimulatory protein bound to the beta-polymerase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.