Enzyme detection device

A method of delecting an enzyme capable of modifying a substrate comprising the steps of:

• (i) providing a substrate comprising an attachment region and a modification region sensitive to modification by the enzyme from an unmodified state to a modified stale;
• (ii) providing a sample suspected of containing the enzyme;
• (iii) providing a substrate recognition molecule to which is coupled a detectable label, wherein the substrate recognition molecule specifically binds the modification region in the unmodified state, the binding site of the substrate recognition molecule being such that the modification region of the substrate is preferentially bound by said substrate recognition molecule as compared with the enzyme when the substrate, substrate recognition molecule and enzyme are mixed, and wherein the substrate recognition molecule sequesters the modifiable region of the substrate, and in doing so it prevents the enzyme from modifying the substrate further;
• (iv) mixing the sample and substrate such that at least some of the enzyme in the sample modifies the substrate;
• (v) depositing the substrate and the substrate recognition molecule on or in a chromatographic medium, wherein the chromatographic medium comprises a first capture recognition molecule immobilised on or in the chromatographic medium, the first capture recognition molecule being capable of binding the attachment region, bringing the substrate and the substrate recognition molecule into contact and detecting the presence of the label wherein detection of the label indicates the absence of the enzyme.