Aminopeptidase from Sphingomonas capsulata.
A novel aminopeptidase with unique substrate specificity was purified from a culture broth of Sphingomonas capsulata. This is the first reported aminopeptidase to demonstrate broad substrate specificity and yet release glycine and alanine with the highest efficacy. On a series of pentapeptide amides with different N-terminal amino acids, this enzyme efficiently releases glycine, alanine, leucine, proline, and glutamate with the lowest turnover value of 370 min(-1) for glutamate. At pH 7.5 (pH optimum) and 25 degrees C, the kinetic parameters for alanine para-nitroanilide were found to be k(cat) = 7600 min(-1) and K(m) = 14 mm. For alanine beta-naphthylamide, they were k(cat) = 860 min(-1) and K(m) = 6.7 mm. Polymerase chain reaction primers were designed based upon obtained internal sequences of the wild type enzyme. The subsequent product was then used to acquire the full-length gene from an S. capsulata genomic library. An open reading frame encoding a protein of 670 amino acids was obtained. The translated protein has a putative signal peptide that directs the enzyme into the supernatant. A search of the amino acid sequence revealed no significant homology to any known aminopeptidases in the available data bases.
Byun
T
T
Novozymes Biotech, Inc., Davis, California 95616, USA.
Tang
M
M
Sloma
A
A
Brown
K M
KM
Marumoto
C
C
Fujii
M
M
Blinkovsky
A M
AM
D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D008969:Molecular Sequence Data; D020578:Sphingomonas / Q000201:enzymology* / Q000235:genetics
D001426:Bacterial Proteins; D018076:DNA, Complementary; D000626:Aminopeptidases