Polypeptides having aminopeptidase activity and nucleic acids encoding same

An isolated polypeptide having aminopeptidase activity obtained from a Sphingomonas strain, selected from the group consisting of:

• (a) a polypeptide having an amino acid sequence which has at least 95% identify with amino acids 33 to 674 of SEQ ID NO:2;
• (b) a polypeptide which is encoded by a nucleic acid sequence which hybridizes under medium stringency conditions with (i) nucleotides 670 to 2592 of SEQ ID NO:1, (ii) its complementary strand;
• or (iii) a fragment consisting of at least 100 contiguous nucleotides of nucleotides 670 to 2592 of SEQ ID NO:1, wherein medium stringency conditions are defined as prehybridization and hybridization at 42° c. in 5× SSPE, 0.3% SDS, 200 μg/ml sheared and denatured salmon sperm DNA, and 35% formamide, and washing with 2× SSC, 0.2% SDS at 55° C.
• (c) an enzymatically active fragment of (a) or (b);
• and
• (d) a polypeptide which (i) has aminopeptidase activity in the pH range between pH 5.0-8.5 measured at 37° C., (ii) has an isoelectric point in the range of 7.4-8.5;
• (iii) has aminopeptidase activity in the temperature range of 20-55° C., measured at pH 7.5 using Gly-para-nitroanilide in Tris-HCl buffer;
• (iv) hydrolyzes ala-para-nitroanilide, Gly-para-nitroanilide, Leu-para-nitroanilide, Glu-para-nitroanilide, Asp-para-nitroanilide, Lys-para-nitroanilide or Pro-para-nitroanilide;
• (iv) is not inhibited by phenylmethanesulfonyl fluoride;
• and (iv) has a molecular mass of 67 ±5 kDa by SDS-PAGE.