Cleavage Tag Guide 

The main cleavage sites used for protelytic cleavage of fusion tags are:

  • Human Rhinovirus 3C Protease (3C / PreScission)
  • Enterokinase (EKT)
  • Factor Xa (FXa)
  • Tobacco Etch Virus Protease (TEV)
  • Thrombin (Thr)


This table below contains some information about each enzyme and its recognition site:

Cleavage Tag Sequence and Cleavage Enzyme Name  Notes
3C (‘PreScission’) cleavage tag LEVLFQ/GP
(/ = main cleavage site)
Human Rhinovirus (HRV) 3C Protease HRV is a highly specific protease that cleaves between the Glu and Gly residues in the cleavage tag. It is often produced with the tradename 'PreScission protease or PSP'.
EKT (Enterokinase) cleavage tag DDDDK/
(/ = main cleavage site)
Enterokinase Enterokinase is an intestinal enzyme normally involved in the protease cleavage of Trypsin. It cleaves after the Lysine (K) in is recognition sequence.
FXa (Factor Xa) cleavage tag IEGR/
(/ = main cleavage site)
Factor Xa Factor Xa cleaves after the Arg residue but can also cleave less frequently at secondary basic sites. Its most common secondary cleavage site is between the Gly and Arg residues in its own recognition site, although the frequency of these events is protein specific.
TEV (tobacco etch virus) cleavage tag ENLYFQ/G
(/ = main cleavage site)
Tobacco etch virus protease Cleavage occurs between the Glu and Gly residues. TEV is often reported to have better specificity for its recognition site compared to EKT, Thrombin or Factor Xa.
Thrombin cleavage tag LVPR/GS
(/ = main cleavage site)
Thrombin Thrombin cleaves preferentially between the Arg and Gly residues. Off target cleavage can occur at non-specific sites, normally from contaminating proteases. To ensure maximal protein integrity the enzyme reagent must be very pure.