A nicking enzyme (or nicking
endonuclease
Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases ...
) is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that cuts one strand of a double-stranded
DNA at a specific recognition
nucleotide
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...
sequences known as a
restriction site Restriction sites, or restriction recognition sites, are located on a DNA molecule containing specific (4-8 base pairs in length) sequences of nucleotides, which are recognized by restriction enzymes. These are generally palindromic sequences (beca ...
. Such enzymes hydrolyse (cut) only one strand of the DNA duplex, to produce DNA molecules that are “nicked”, rather than cleaved.
They can be used for strand-displacement amplification,
Nicking Enzyme Amplification Reaction Nicking Enzyme Amplification Reaction (NEAR) is a method for ''in vitro'' DNA amplification like the polymerase chain reaction (PCR). NEAR is isothermal, replicating DNA at a constant temperature using a polymerase (and nicking enzyme A nicking en ...
, exonucleotyic degradation, the creation of small gaps,
or
nick translation
Nick translation (or head translation), developed in 1977 by Peter Rigby and Paul Berg, is a tagging technique in molecular biology in which DNA Polymerase I is used to replace some of the nucleotides of a DNA sequence with their labeled analogu ...
.
The latter process has been successfully used to incorporate both radioactively labelled nucleotides and fluorescent nucleotides allowing specific regions on a double stranded DNA to be studied.
Over 200 nicking enzymes have been studied, and 13 of these are available commercially
and are routinely used for research and in commercial products.
References
{{reflist
External links
New England Biolabs Nicking EnzymesFermentas Nicking Enzymes
Molecular biology
Biotechnology
Enzymes