The present invention relates to a polypeptide consisting of or comprising a variant of human trypsinogen-1, wherein the variant is characterized in that an amino acid residue selected from A16, A17, K64, K138, N139, L142 and L147 is replaced by an amino acid residue with a negatively charged side chain and/or H18 is replaced by a glutamine or asparagine residue and/or L107 is replaced by an amino acid residue with a positively charged side chain and/or N139 is replaced by an amino acid residue with an aromatic side chain, wherein the variant is cleavable into a polypeptide having a native-like enzymatic activity when compared to human trypsin-1. The present invention further relates to means and method for manufacturing the polypeptide as well as the use of the polypeptide, particularly in an immunoassay.