School of Science Department of Chemistry 9 Design of Controllable Enzymes for Therapeutic Applications Supervisor: VONG Kenward King Ho / CHEM Student: WAN Kai Yui / IRE Course: UROP1000, Summer Stroke is a serious and fatal disease, but antithrombotic agents can be applied to interrupt plaque formation to significantly reduce mortality rates. The protease known as nattokinase is also a viable antithrombotic agent, but may cause brain bleeding from excessive protease activity. In this UROP project, a modified nattokinase will be produced using recombinant DNA technology. Following expression in Escherichia coli, protein purification was performed using techniques like Fast Protein Liquid Chromatograph (FPLC), centrifugal filtration, and High-Performance Liquid Chromatography (HPLC). The goal of this project was to optimize purification conditions for these therapeutic proteins.