Magnetic microsphere for immobilizing earthworm fibrinolytic enzyme and preparation method thereof

The invention discloses a magnetic microsphere for immobilizing earthworm fibrinolytic enzyme and a preparation method thereof. Enzymatic activity of the magnetic microsphere is 25-35 U/mg. The preparation method comprises the following steps: firstly dissolving a mung bean trypsin inhibitor in a buffer solution of pH 3-9 so as to obtain a protease buffer solution, adding the protease buffer solution into activated magnetic chitosan microspheres, carrying out water-bath shaking and coupling for 2-14 h so as to obtain mung bean trypsin inhibitor-coupled magnetic chitosan microspheres; adding the mung bean trypsin inhibitor-coupled magnetic chitosan microspheres into a crude enzyme solution of earthworm fibrinolytic enzyme and shaking in a thermostatic shaking bath of 30-60 DEG C and carrying out a curing reaction for 0.5-3 h; repeatedly washing after the reaction until no protein is detected from the washing liquid, and carrying out magnetic separation and collection so as to obtain the magnetic microsphere for immobilizing earthworm fibrinolytic enzyme. According to the invention, the mung bean trypsin inhibitor used as ligand is coupled with the magnetic microsphere, and the magnetic microsphere is used in separation and purification of earthworm fibrinolytic enzyme to enhance separation and purification selectivity of earthworm fibrinolytic enzyme. In addition, the magnetic microsphere is easy to separate from earthworm fibrinolytic enzyme.