Fig. 4

Urea inhibits intein self-cleavage of CI-DPIP. a: SDS-PAGE analysis of cleavage in the buffer with different concentrations of urea. M: Molecular weight markers. Lane 1: input. Lanes 2 and 3: resin after cleavage by 2 M and 1 M urea-containing buffers. 4: resin after cleavage without urea. b: calculated cleavage ratio of every cleavage reaction. All the cleaving reaction was completed in the TGE buffer (pH 5.5) at 25 °C for 2 days