This document summarizes the effects of various enzymes on blood antigens. It notes that the M and N antigens are easily destroyed by common blood bank enzymes like ficin, papain and bromelin. The S and s antigens are also degraded by these enzymes but to a lesser extent and depending on enzyme strength. Fy a and Fy b antigens are destroyed by proteolytic enzymes like ficin, papain, bromelin and chymotrypsin. In contrast, treatment with ficin and papain enhances the reactivity of I and i antigens with antibodies. While the P1 antigen is resistant to enzyme treatment, the reactivity of antibodies can be enhanced against enzyme-treated cells. Similarly, papain and fic