The invention relates to a
plant proteinase extraction method and obtained
plant proteinase. The method comprises the following steps: mixing
slurry or a crushed material of plants with water in a
solid-
liquid ratio of 1:(5-20), then carrying out
water extraction, and collecting an extracting solution; filtering the obtained extracting solution by virtue of a plate-and-frame
filter press and a
ceramic membrane sequentially, wherein the pore size of filter cloth of the plate-and-frame
filter press is 100-150 meshes, and the pore size of the
ceramic membrane is 50-200nm; carrying out primary
ultrafiltration treatment on a filtrate by using an
ultrafiltration membrane with the molecular weight cutoff of 30-100KDa, collecting the filtrate, carrying out secondary
ultrafiltration treatment on the filtrate by using an ultrafiltration membrane with the molecular weight cutoff of 5-15KDa, and collecting trapped fluid; and concentrating the trapped fluid to obtain a concentrated solution, and carrying out
freeze drying on the concentrated solution, so that the
plant proteinase is obtained. The method provided by the invention has the advantages of simple technology, no
pollution to the environment, the feasibility of large-scale industrial production and high
proteinase activity and purity. The plant proteinase has the advantages of good activity, high purity and no
solvent residue and meets usage requirements of the food, daily chemical and
medicine industries.