Degradation of recombinant DGAT1 in the soluble fraction of E. coli. Plasmids pMBP-DGAT1-His and the empty vector pMAL-c2X were transformed into E. coli BL21(DE3). Protein expression was induced by IPTG for various times. "+" and "-" represent protein induction with or without IPTG. SDS-PAGE (10%) was used for the separation of proteins. (A) Immunoblotting detection of rDGAT1. Recombinant DGAT1 in the 10,000g supernatant of E. coli transformed with pMBP-DGAT1-His was identified by polyclonal antibodies raised against MBP-mTTP fusion protein [2, 3]. Partially purified MBP-mTTP was used as a positive control for immunoblotting. The full-length rDGAT1 is marked with an arrow. (B) Coomassie brilliant blue staining of proteins in the 10,000g supernatants of E. coli transformed with pMBP-DGAT1-His. (C) Coomassie brilliant blue staining of proteins in the 10,000g supernatants of E. coli transformed with pMAL-c2X as an empty vector control for the expression of MBP.