title: Host specificity of DNA produced by Escherichia coli. XI. In vitro modification of phage fd replicative form.
abstract: An enzymatic activity, having the properties expected of a B-specific host-controlled modification enzyme, has been purified from an extract of Escherichia coli strain B. This activity renders the unmodified replicative form of phage fd resistant to B-specific restriction and is only present in strains carrying intact genes for type B modification. In phosphate buffer, the enzyme acts optimally at pH 6 and is dependent upon a single cofactor, S-adenosylmethionine.
mesh_terms: D002845:Chromatography; D003090:Coliphages; D004261:DNA Replication; D004269:DNA, Bacterial; D003956:Dialysis; D004798:Enzymes / Q000302:isolation & purification; D004926:Escherichia coli / Q000201:enzymology*; D066298:In Vitro Techniques
chemical_list: D004269:DNA, Bacterial; D004798:Enzymes