Abstract: The present invention relates to the use of an esterase for monitoring and/or tracking the synthesis of a protein, polypeptide or peptide in a cell-free translation system or in an in vivo expression system in which the synthesis of a protein, polypeptide or peptide can occur, wherein said monitoring and/or tracking comprises the detection of the function of said esterase. The present invention further relates to a vector comprising a nucleic acid molecule coding for an esterase and expressing an esterase fusionprotein. Moreover, the present invention relates to a vector comprising a nucleic acid molecule coding for an esterase and comprising in frame at least one multiple cloning site for a further protein/polypeptide/peptide, to be expressed in form of a fusion protein comprising said esterase (esterase activity) and said further proteinaceous peptide structure. The present invention also provides for a protein, polypeptide or peptide encoded by the vectors of the present invention.

Abstract: A system with immobilized DNA is used in the fields of medicine, environmentology or criminology as an analytical tool in the analysis of nucleic acid. The immobilized DNA is provided with a biocatalytically active marker, such as an enzyme, an with an inhibitor substance which reversibly inhibits catalytic activity, or in addition to the immobilized biocatalytic marker, the immobilized DNA is provided with a substance which can reversibly inhibit the catalytic activity of the marker. Alternatively, an immobilized biocatalytically active marker can be provided with DNA as a scavenger which includes a substance as an inhibitor which can reversibly inhibit the activity of the marker. In another alternative, it is possible to use a complex including a molecule binding double-stranded DNA and a substance as an inhibitor which can reversibly inhibit the activity of the marker by interacting with the immobilized biocatalytically active marker.