Aspergillus phenylalanine aminopeptidase
The present invention describes isolated polypeptides from fungi which have aminopeptidase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods for producing and using the polypeptides.
1. An isolated polypeptide which has phenylalanine aminopeptidase activity, selected from the group consisting of:
(a) an isolated polypeptide from Aspergillus which has an amino acid sequence which has at least 80% amino acid sequence identity with amino acids 1 to 663 of SEQ ID NO:2; and
(b) an isolated polypeptide from Aspergillus which is encoded by a polynucleotide which polynucleotide hybridizes under conditions of 6×SSC +0.5% SDS at 56°C. with a polynucleotide having the nucleotide sequence of SEQ ID NO:1
wherein the isolated polypeptide is substantially free of a contaminating amyloglucosidase.
2. A polypeptide of claim 1 which has at least one of the following physicochemical properties:
(1) a molecular weight (when deglycosylated) of approximately 72 kDa; and
(2) an isoelectric point of about 5.6.
3. A polypeptide of claim 2 , wherein 90% of phenylalanine aminopeptidase activity is retained after incubation for 60 minutes at 50° C.
4. The polypeptide of claim 1 , comprising the amino acid sequence of SEQ ID NO:2.
5. An isolated polynucleotide comprising a nucleic acid sequence which encodes the polypeptide of claim 1 .
6. A nucleic acid construct comprising the polynucleotide of claim 5 operably linked to one or more control sequences that direct the production of the polypeptide in a suitable expression host.
7. A recombinant expression vector comprising the nucleic acid construct of claim 6 .
8. An isolated recombinant host cell comprising the nucleic acid construct of claim 6 .
9. A method for producing a polypeptide with aminopeptidase activity comprising cultivating the recombinant host cell of claim 8 to produce a supematant and/or recombinant host cells comprising the polypeptide; and recovering the polypeptide.
10. A polypeptide produced by the method of claim 9 .
11. A food composition comprising the polypeptide of claim 1 .
12. The food composition of claim 11 , which is a dough or a baked product thereof.
13. The food composition of claim 11 , which is a cheese.
14. A food composition comprising the cells of claim 8 .
15. The food composition of claim 14 , which is a dough or a baked product thereof.
16. The food composition of claim 14 , which is a cheese.
17. The polypeptide of claim 1 , which has at least 95% identity with amino acids 1–663 of SEQ ID NO:2.