Linked Life Data

322735

Source:http://linkedlifedata.com/resource/pubmed/id/322735

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1977-6-30
pubmed:abstractText
Fractionation and purification of DNA methylases and specific endonucleases from E. coli SK responsible for DNA specificity to host prokaryotic cells were studied. The most efficient purification was achieved by precipitation of proteins by 0.6 saturated ammonium sulfate with subsequent chromatography on KM-cellulose and concentration of fractions by dialysis against glycerol. Under these conditions the methylase activity produced 4 discrete fractions. Due to purification the specific activity of methylases increased 11--20-fold in various fractions. Methylase from the first (A) and fourth (BII) peaks catalyzed the methylation of cytosine to produce 5-methylcytosine; methylase from the third peak (BI) methylated adenine to produce 6-methylaminopurine. The chemical specificity of the second peak (B) methylase could not be established due to very high lability of the enzyme in this fraction. Specific endonuclease was found in the gradient zones eluted by 0.1--0.2 M and 0.65--0.75 M NaCl. It is assumed that those enzymes providing for DNA hydrolysis up to the formation of high--molecular discrete fragments, are restricting endonucleases of the SK system. The results obtained strongly suggest the existence of several types of methylases and restricting endonucleases in E. coli SK cells.
pubmed:language
rus
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0320-9725
pubmed:author
pubmed:issnType
Print
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
598-608
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
[Fractionation and purification of DNA methylases and specific endonucleases from cells of Escherichia coli SK].
pubmed:publicationType
Journal Article, English Abstract