Figure 4
The LC-MS/MS spectrometry analysis of the extra 162 Da mass on N-terminal AGS of rTFF1. (a) BC (pNCMO2-TFF1); and (b) glycoprotein stain analysis. The rTFF1 protein purified from B. choshinensis (pNCMO2-TFF1) by native Ni-NTA affinity chromatography was dialyzed against PBS buffer (50 mM Na2HPO4-NaH2PO4, pH 7.0) then analyzed by LC-MS/MS spectrometry (a) and confirmed by glycoprotein staining method (Pierce, USA). In (b), the positive control (+) was horseradish peroxidase and the negative control (−) was soybean trypsin inhibitor. The TFF1/BC and TFF1/EC represented rTFF1 proteins purified from B. choshinensis (pNCMO2-TFF1) and from BL21(DE3) (pET-TFF1), respectively.