ENTRY       EC 3.1.21.3
NAME        Type I site-specific deoxyribonuclease
            Type I restrinction enzyme
            Deoxyribonuclease (ATP- and S-adenosyl-L-methione-dependent)
            Restriction-Modification system
CLASS       Hydrolases
            Acting on ester bonds
            Endodeoxyribonucleases producing 5'-phosphomonoesters
REACTION    Endonucleolytic cleavage of DNA to give random double-stranded
            fragments with terminal 5'-phosphates; ATP is simultaneously
            hydrolysed.
SUBSTRATE   DNA
            ATP
            H2O
            dATP
PRODUCT     DNA
            ADP
            Orthophosphate
COFACTOR    S-Adenosyl-L-methionine
COMMENT     This is a large group of enzymes which, together with those now
            listed as EC 3.1.21.4 and 3.1.21.5, were previously listed
            separately in sub-subclasses 3.1.23 and 3.1.24. They have an
            absolute requirement for ATP (or dATP) and
            S-adenosyl-L-methionine. They recognize specific short DNA
            sequences and cleave at sites remote from the recognition
            sequence. They are multifunctional proteins which also catalyse
            the reactions of EC 2.1.1.72 and 2.1.1.73, with similar site
            specificity. A complete listing of all these enzymes
            has been produced by R.J.Roberts; this list is updated annually.
GENES       MJA: MJ0130 MJ1214 MJ1220
            MTH: MTH940 MTH941 MTH942
            ECO: b4350(hsdR)
            MPN: H91_orf206(hsdR) H91_orf376(hsdR)
            SYN: sll1562 slr0468
DBLINKS     University of Geneva ENZYME DATA BANK: 3.1.21.3
            WIT (What Is There) Metabolic Reconstruction: 3.1.21.3
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