2. Tissue crushing: put the frozen pig spleen sample into a mortar, add a proper amount of grinding liquid (such as grinding buffer), and crush the tissue with ultrasonic wave or stirrer to break the cell wall and release protein.
3. protein extraction: centrifuge the broken tissue, collect the supernatant, and add an appropriate amount of acidic solution such as hydrochloric acid or trifluoroacetic acid to precipitate protein. And then washing the precipitate with an organic solvent such as ethanol or acetone to remove impurities.
4. protein purification: protein precipitate was dissolved in a proper amount of buffer, and then purified by ion exchange chromatography, gel filtration chromatography, affinity chromatography and other methods to obtain purified porcine spleen peptide.