The present invention relates to a genetically modified plant or plant cell derived from a wild-type plant or plant cell, said wild-type plant or plant cell producing at least one serine protease comprising the motif SSRGPX.sub.1LKPDX.sub.2X.sub.3APGX.sub.4SGTSMSCPHX.sub.5PX.sub.6WSPX.sub.7AX.sub.8X.sub.9SAX.sub.10MTT (SEQ ID No. 1), wherein X.sub.1 is a peptide consisting of 7 amino acid residues, X.sub.2 is I or L, X.sub.3 is T or M, X.sub.4 is a peptide consisting of 27 or 28 amino acid residues, X.sub.5 is a peptide consisting of 12 amino acid residues, X.sub.6 is T or E, X.sub.7 is S or A, X.sub.8 is V or I, X.sub.9 is K or R and X.sub.10 is I or M, wherein the proteolytic activity of the at least one serine protease in the genetically modified plant or plant cell is reduced compared to its activity in the wild-type plant or plant cell, wherein the genetically modified plant or plant cell comprises at least one exogenous nucleic acid molecule encoding for at least one protein or polypeptide of interest.

The present invention discloses a complex with a stroke therapeutic characteristic, and a preparation method and use thereof. The complex is a complex of a yeast peptide and hydroxytyrosol. The yeast peptide is a yeast peptide with a molecular weight less than 3 kDa produced by papain enzymolysis of yeast protein. The pH during enzymatic hydrolysis is 6.8-7.2, the enzymatic hydrolysis time is 3.8-6.2 h, the enzymatic hydrolysis temperature is 48-58 C., and the ratio of the papain to the yeast protein in the enzymatic hydrolysis system is 8,800-9,200 U/g. The complex is used for manufacture of a drug for treating ischemic stroke. The present invention offers an efficient, safe, and cost-effective complex with a stroke therapeutic characteristic, featuring broad application prospects, and significant technical advantages, and the complex has a simple preparation method and low production cost.