Addition of tags [such as His (histidine) tags] is extremely helpful for the affinity purification of recombinant proteins. In several cases, these tags must be removed before performing functional and structural studies. The enzyme most frequently used to cleave tags of recombinant proteins is the TEV-protease (tobacco-etch-virus NIa protease). The continuous production of this enzyme in soluble form is quite an expensive process and not easily accessible to many laboratories. Thus an interesting alternative is the use of TEV-protease in an immobilized form, which may be reutilized several times. The main objective of the present study was to obtain a TEV-protease in an immobilized form, by covalent immobilization on to solid supports through selective use of different amino acid residues, lysine or cysteine. High protein immobilization yields (75-97%) were obtained with both strategies. The TEV-protease immobilized through its exposed cysteine thiol groups maintained its ability for cleaving a 20 kDa substrate. While the activity of the immobilized TEV-protease maintained only 30% of the activity of the enzyme in soluble form, its stability at 4 degrees C was improved three times. Moreover, this enzyme could be reutilized in at least five cycles of cleavage without loss of performance. The present results indicate that the use of a TEV-protease in an immobilized form is a potentially useful tool for the cleavage of His tags of recombinant proteins and may be useful for reducing the cost of the total process of cleavage.