FIG. 5.

Time course of in vitro processing of inactive wild-type TGAH fusion precursor expressed from plasmid pSERH (A) and enzyme activity as a function of refolding time (B). (A) Purified inactive wild-type TGAH fusion precursor was renatured at each indicated time and immediately mixed and boiled for 10 min with sample application buffer for SDS-PAGE. The conversion of the TGAH fusion precursor to TGα and Hβ subunits was monitored by SDS-PAGE. Lane M, molecular mass markers. The arrows, from the top to the bottom, indicate unprocessed fusion precursor, Hβ subunit, and TGα subunit, respectively. (B) The enzyme activity of each refolding mixture at various times was assayed as described in Materials and Methods.