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noun, plural: helicases

An enzyme that utilizes energy from nucleoside triphosphate (e.g. ATP) hydrolysis in order to unwind the two annealed nucleic acid strands (e.g. DNA)


DNA is a helical, double-stranded molecule that bears the genetic code. During the replication of DNA, its two strands are separated from each other resulting in a configuration called the replication fork. The replication fork is comprised of two prongs wherein each prong is the single strand of DNA. The replication fork results from the work of the helicases. Helicases are enzymes that are used by living organisms to separate the strands of nucleic acids, and in this case, the double-stranded DNA. Helicases do so by breaking the hydrogen bonds that hold the two strands together. Helicases are able to do this by utilizing energy from the hydrolysis of nucleoside triphosphates (e.g. ATPs). Apart from DNA replication, helicases are also used in transcription, translation, recombination, DNA repair, and ribosome biogenesis. DNA helicases were first discovered and isolated in E.coli in 1976.1

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1 Abdel-Monem M, Dürwald H, Hoffmann-Berling H (June 1976). "Enzymic unwinding of DNA. 2. Chain separation by an ATP-dependent DNA unwinding enzyme". Eur. J. Biochem. 65 (2): 441–9.