The synthesized PcTS1 gene was used for site-directed mutagenesis, and overlapped PCR was conducted using TransStar FastPfu Fly DNA polymerase. The PCR products were then purified through gel extraction and inserted into a linearized pET28a vector via BamHI and HindIII digestion. After transforming these constructs into E. coli Turbo and confirming them through DNA sequencing, we obtained the desired plasmids. Only plasmids with correct sequences were selected for protein expression in E. coli BL21Gold(DE3), which was subsequently analyzed by HPLC. The primer sequences used are detailed in Table .