Aspergillus niger proline protein endopeptidase and preparation method thereof

The invention relates to Aspergillus niger proline-specific endoprotease and the preparation method thereof, which belong to the field of genetic engineering and enzymology. The Aspergillus niger proline-specific endoprotease is selected from amino acid sequence of Aspergillus niger proline-specific endoprotease with a sequence code of SEQ ID No.2, wherein the amino acid sequence has nucleotide sequences represented by the first to the 1,581 in SEQ ID No.1, and has polypeptides of amino acid sequence represented by SEQ ID No.2. Test shows that haze protein bands with molecular weight of 8to 14 kDa are disappeared completely after SDS-polyacrylamide gel electrophoresis detection of beer protein added with PEP, which shows that the haze activity protein rich in proline residues is hydrolyzed completely by PEP, and primarily testifies that proline-specific endoprotease can specifically cut protein and proline residues at carbon terminal of a peptide chain, and can eliminate cold haze substance in beer.