One unit of enzyme cleaves > 90% of 100 µg of a test GST-tagged protein when incubated in 1× PBS at 22°C for 16 h.
Thrombin solution: Dissolve 500 units in 0.5 mL of PBS prechilled to 4°C. Swirl gently. Store solution in small aliquots at -80°C to preserve activity.
Cleavage buffer: PBS (140 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 1.8 mM KH2PO4) pH 7.3.
Elution buffer: 50 mM Tris-HCl, 10 mM reduced glutathione, pH 8.0