Engineered enzymes and uses thereof

A recombinant engineered enzyme with catalytic activity of defined specificity, characterized by a combination of the following components:

• (a) a protein scaffold capable of catalyzing at least one protein cleavage reaction on at least one target substrate and being a serine protease of the structural class S1, and
• (b) one or more specificity determining regions (SDRs), wherein the SDRs are peptide sequences inserted into the protein scaffold at one or more positions that correspond structurally or by amino acid sequence homology to the regions 38-48 and 122-130 in human trypsin I having the amino acid sequence shown in SEQ ID NO:1, wherein the inserted SDRs enable the resulting engineered protein to discriminate between at least one target substrate and one or more different substrates.