Abstract: The present invention provides a detection reagent for detection of the presence of a substance of interest in a sample. The detection reagent comprises a binding portion, a linking portion, and a catalytic portion. The linking portion comprises a cleavage site for cleavage of the binding portion from the catalytic portion. According to the method, the detection reagent is caused to bind to the substance of interest. The bound reagent is then cleaved by breaking of a bond in the linking portion. Upon cleavage, the catalytic portion is removed from the binding reaction mixture and caused to catalyze a reaction that produces a detectable product.