WHEREAS THE monitoring methods described so far (on-line and off-line reaction monitoring) do not provide information concerning the middle- and long-range specificity of a polymer cleaving enzyme, these can be achieved using cleavage pattern analysis (CPA). The investigation of cleavage products of ribonucleases and protease was used to obtain sequence information of biopolymers[94]. Using this technique in the opposite direction with a known sequence provides information on the preference of the enzyme under investigation[65]. Exploring the specific cleavage products of a defined substrate provides information on the specificity and the mechanism of the cleaving enzyme. CPA is performed using MALDI-MS, which allows the use of almost all kinds of substrates, limited only by the capabilities of the instrument used regarding the mass range and resolution and the ionisability of the substrate and putative cleavage products.