flaskIn order to ascertain the viability of the ELP-intein system forproduction of the peptide Pa-MAP 2 through ELP-intein system, theplasmid pET21-60EGP was designed (see Fig. S1), synthetized andcloned into E. coli BL21 via heat shock transformation. Firstly, LB andTerrific Broth (TB) media without glycerol were selected for bacte-rial growth. Nevertheless, ELP-fusion production was not detectedafter induction with 1 mM IPTG (data not shown). In TB supple-mented with glycerol, expression of 60EGP was detected within15 min (Fig. 1A, lane 3), reaching its maximum at 1 h (Fig. 1A, lane5), remaining relatively constant until 4 h (Fig. 1A, lanes 6 to 8). Thewhole protein extracts were loaded into a 12% SDS-PAGE.