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EC 5.99.1.2 Details

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EC number

5.99.1.2

Accepted name

DNA topoisomerase

Reaction

ATP-independent breakage of single-stranded DNA, followed by passage and rejoining

Other name(s)

type I DNA topoisomerase, untwisting enzyme, relaxing enzyme, nicking-closing enzyme, swivelase, ω-protein, deoxyribonucleate topoisomerase, topoisomerase

Systematic name

DNA topoisomerase

CAS registry number

80449-01-0

Comment

These enzymes bring about the conversion of one topological isomer of DNA into another, e.g., the relaxation of superhelical turns in DNA, the interconversion of simple and knotted rings of single-stranded DNA, and the intertwisting of single-stranded rings of complementary sequences, cf. EC 5.6.1.2.2 DNA topoisomerase (ATP-hydrolysing).

History

created 1984, deleted 2018

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.1.1 With NAD⁺ or NADP⁺ as acceptor

1.1.2 With a cytochrome as acceptor

1.1.3 With oxygen as acceptor

1.1.4 With a disulfide as acceptor

1.1.5 With a quinone or similar compound as acceptor

1.1.7 With an iron-sulfur protein as acceptor

1.1.9 With a copper protein as acceptor

1.1.98 With other, known, physiological acceptors

1.1.99 With unknown physiological acceptors

1.2 Acting on the aldehyde or oxo group of donors

1.3 Acting on the CH-CH group of donors

1.4 Acting on the CH-NH₂ group of donors

1.5 Acting on the CH-NH group of donors

1.6 Acting on NADH or NADPH

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.9 Acting on a heme group of donors

1.10 Acting on diphenols and related substances as donors

1.11 Acting on a peroxide as acceptor

1.12 Acting on hydrogen as donor

1.13 Acting on single donors with incorporation of molecular oxygen (oxygenases)

1.14 Acting on paired donors, with incorporation or reduction of molecular oxygen

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.17 Acting on CH or CH₂ groups

1.18 Acting on iron-sulfur proteins as donors

1.19 Acting on reduced flavodoxin as donor

1.20 Acting on phosphorus or arsenic in donors

1.21 Catalysing the reaction X-H + Y-H = X-Y

1.22 Acting on halogen in donors

1.23 Reducing C-O-C group as acceptor

1.97 Other oxidoreductases

1.97.1 Sole sub-subclass for oxidoreductases that do not belong in the other subclasses

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)

5.1 Racemases and epimerases

5.2 cis-trans-Isomerases

5.3 Intramolecular oxidoreductases

5.4 Intramolecular transferases

5.5 Intramolecular lyases

5.6 Isomerases altering macromolecular conformation

5.99 Other isomerases

5.99.1 Sole sub-subclass for isomerases that do not belong in the other subclasses

5.99.1.1 thiocyanate isomerase

5.99.1.2 DNA topoisomerase

5.99.1.3 DNA topoisomerase (ATP-hydrolysing)

5.99.1.4 2-hydroxychromene-2-carboxylate isomerase

6 Ligases

7 Translocases