Engineering Research Centre of Molecular Medicine of Ministry of Education 1 article published in JoVE Biochemistry Affinity Purification of a Fibrinolytic Enzyme from Sipunculus nudus Mingqing Tang1,2, Hongjun Lin1, Chengjia Hu1, Hui Yan1,2 1Medicine School, Huaqiao University, 2Engineering Research Centre of Molecular Medicine of Ministry of Education Here, we present an affinity purification method of a fibrinolytic enzyme from Sipunculus nudus that is simple, inexpensive, and efficient.