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NAR Molecular Biology Database Collection entry number 224
Roberts, Rich; Posfai, Janos; Vincze, Tamas; Macelis, Dana
New England Biolabs, 240 County Road, Ipswich, MA 01938-2723, USA

Database Description

REBASE is a comprehensive database of information about restriction enzymes, DNA methyltransferases and related proteins involved in the biological process of restriction-modification. It contains fully referenced information about recognition and cleavage sites, isoschizomers, neoschizomers, commercial availability, methylation sensitivity, crystal and sequence data. Experimentally characterized homing endonucleases are also included. All newly sequenced genomes are analyzed for the presence of putative restriction systems and this data is included within REBASE.
The contents of REBASE may be browsed from the web ( and selected compilations can be downloaded by ftp ( Additionally, monthly updates can be requested via email.
Currently, there are 19,442 enzymes (including subunits) and 10,032 references stored in REBASE. The references are collected from journals, books, patents, as well as unpublished observations.
There are currently 3,945 biochemically or genetically characterized restriction enzymes in REBASE and of the 3,698 Type II restriction enzymes, 641 are commercially available, including 235 distinct specificities.
Among the 5,105 restriction enzyme genes and 8,022 DNA methyltransferase genes that can be identified in GenBank, the sequenced microbial genomes now account for 9,597 of these genes!
The number of sequenced bacterial and archaeal genomes has risen to more than 1,000 and the total number of complete restriction-modification (R-M) systems in REBASE is now almost 4,000 for well-characterized systems and more than 5,800 for putative R-M systems, whose existence is predicted on the basis of a bioinformatic analysis of DNA sequences in GenBank.

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