(A) Expression of Stv-43 in E. coli carrying expression vector pTSA-43. Total cell protein of BL21(DE3)(pLysE), with or without pTSA-43, was analyzed by SDS/PAGE (31). Lanes: a, BL21(DE3)(pLysE); b, BL21(DE3)(pLysE)(pTSA-43); and M, molecular mass standard proteins. The number above each lane is the time in hours after induction. The position where Stv-43 migrates is shown by an arrow. Each lane contains the total cell protein from the following volume of culture: at 5 hr for a and at 3 hr and 5 hr for b, 25 μl; at 0 hr and 1 hr for b, 83 μl. (B) SDS/PAGE analysis of purified Stv-43. Approximately 1 μg of purified Stv-43 was analyzed. The right lane contains molecular mass standard proteins.