The endonuclease scission of magnetic particles functionalized with sequence -specific DNAs, which are associated on cantilevers, is followed by the magnetic force-amplified readout of the reactions by the nano-mechanical deflection/retraction of the cantilevers. The systems are employed to develop AND or OR logic gates and to detect single base mismatch specificity of the endonucleases. The two endonucleases EcoRI (E-A) and Ascl (E-B) are used as inputs. The removal of magnetic particles linked to the cantilever by the duplexes 1/1a and 2/2a via the simultaneous cleavage of the DNAs by E-A and E-B leads to the retraction of the magnetically deflected cantilever and to the establishment of the "AND" gate, The removal of the magnetic particles linked to the cantilevers by the duplex 3/3a by either E-A or E-B leads to the retraction of the magnetically deflected cantilever and to the establishment of the "OR" gate. The magnetic force-amplified readout of endonuclease activities is also employed to reveal single base mismatch specificity of the biocatalysts.