Mutant Alfimeprase engineering strain, and preparation method and applications thereof

The invention relates to a preparation method of a recombinant viper venom protein. A mutant Alfimeprase gene of artificially synthesized Agkistrodon contortrix is utilized, and the gene has the nucleotide sequence shown as SEQ ID No.2. The gene is linked to yeast expression plasmids pPIC9K to construct a high efficiency expression vector pPIC9K-His-Alf, a Pichia yeast strain GS115 is introduced, and the vector is named as FY-Alf. Induced expression is carried out with methanol, the expressed recombinant protein is purified and then subjected to activity verification by a fibrin plate assay, and the result shows that the recombinant protein Alfimeprase expressed by the yeast strain GS115 containing pPIC9K-His-Alf plasmids has high fibrinolytic activity.