The release of oligonucleotides by theEscherichia coli B restriction endonuclease

TheEscherichia coli B (Eco B) restriction endonuclease releases approximately 75 nucleotides as acid-soluble oligonucleotides for each single-strand endonucleolytic scission that it catalyzes. This reaction, like the endonucleolytic cleavage, requires ATP, Mg⁺⁺, S-adenosylmethionine, and unmodified DNA containing appropriate specificity sites. Like the endonuclease reaction, the release of oligonucleotides terminates after roughly 5 minutes. The acid-soluble oligonucleotides have an average chain length of roughly 7, and an apparently random base composition.