Preparation method of magnetic microspheres for immobilizing earthworm fibrinolytic enzyme

The invention discloses a preparation method of magnetic microspheres for immobilizing earthworm fibrinolytic enzyme. The preparation method comprises the following steps: firstly dissolving pig lung aprotinin in a buffer solution of pH 7-9 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 4-8 h so as to obtain pig lung aprotinin coupled magnetic chitosan microspheres; adding the pig lung aprotinin 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 magnetic microspheres for immobilizing earthworm fibrinolytic enzyme. Enzymatic activity is 15-30 U/mg. According to the invention, pig lung aprotinin used as ligand is coupled with the magnetic microspheres, and the magnetic microspheres are used in separation and purification of earthworm fibrinolytic enzyme to enhance separation and purification selectivity of earthworm fibrinolytic enzyme. In addition, the magnetic microspheres are easy to separate from earthworm fibrinolytic enzyme.