Gene for coding serpin and application thereof

The invention relates to a gene spilC for coding serpin activity, which is provided with one of the following nucleotide sequences: 1) DAN sequence of sequence table No.1; 2) amino acid residue sequence of sequence table No.2 with one or more replaced, deficient and/or added amino acid residue and protein having the serpin activity. DAN in sequence 1 in the sequence table is started from one hundred eleventh ribonucleotide from 5' end through a starting codon ATG and is ended with an ending codon TAA to the 755 base, a complete ORF (ribonucleotide 111 to 755), the one hundred eleventh to one hundred thirteenth ribonucleotide from the 5' end is of a starting codon ATG of the spilC gene, and seven hundred fifty third to seven hundred fifty fifth ribonucleotide from the 5' end is of an ending codon TAA of the spilC gene. The novel serpin and the coded gene thereof have wide application on the aspects for playing the active defense effect of the host cell for the infection process of the pathogenic microorganism.