Digestion by three proteases, HRV 3C protease, thrombin, and factor Xa. M: molecular size markers, 1: purified LDH with TF tag, 2: digestion by 0.1 U of HRV 3C, 3: digestion by 1 U of HRV 3C, 4: digestion by 5 U of HRV 3C, 5: digestion by 0.1 U of thrombin, 6: digestion by 1 U of thrombin, 7: digestion by 5 U of thrombin, 8: digestion by 0.1 U of factor Xa, 9: digestion by 1 U of factor Xa, 10: digestion by 5 U of factor Xa.