Magnetic microsphere for earthworm fibrinolytic enzyme immobilization and preparation method thereof

The invention discloses a magnetic microsphere for earthworm fibrinolytic enzyme immobilization and a preparation method thereof. Enzymatic activity of the magnetic microsphere is 40-60 U/mg. The preparation method comprises the following steps: firstly dissolving a sagittaria sagittifolia trypsin inhibitor 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 4-7 h so as to obtain sagittaria sagittifolia trypsin inhibitor-coupled magnetic chitosan microspheres; adding the sagittaria sagittifolia 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 earthworm fibrinolytic enzyme immobilization. According to the invention, the sagittaria sagittifolia trypsin inhibitor 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.