SuperSAP, a new formulation for DNA dephosphorylation, removes 5' phosphates from protruding-, blunt- or recessed ends in just 5 minutes at 37 C. It works directly in restriction enzyme digests, and can be added directly to simultaneously cut and dephosphorylate DNA. No additional buffers or additives are required. SuperSAP is completely heat-inactivated at 65 C. It has all the benefits of SAP with high specific activity and simple heat-inactivation. No purification is necessary prior to ligation.