An abzyme (from antibody and enzyme), also called catmab (from catalytic monoclonal antibody), is a monoclonal antibody with catalytic activity. Abzymes are usually artificial constructs, but are also found in normal humans (anti-vasoactive intestinal peptide autoantibodies) and in patients with the autoimmune disease systemic lupus erythematosus, where they can bind and hydrolize DNA. Abzymes are a potential tool in biotechnology, e.g., to perform specific actions on DNA.