Characterization and mass spectrometry analysis of aminopeptidase N from Pseudomononas putida lup
Urszula Jankiewicz , Maria Swiontek Brzezinska , Ewa Beata Górska, Paweł Kowalczyk Pol J Microbiol 2013; 62 (4): ICID: 1087834 Article type: Original article IC™ Value: 10.00
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Abstract: An intracellular aminopeptidase N synthesized by Pseudomonas putida lup was purified and characterized. The purified approx. 150–fold enzyme showed highest activity against A-β-naphthylamide at pH 7.5 and at temperature 40 °C C and was 100% stable thermally for 240 min at 40 °C. P. putida lup aminopeptidase N is a monomer with mass approx. 99 kDa determined by SDS–PAGE and gel permeation chromatography. The enzyme has broad substrate specificity, but is the most active against protein substrates with N-terminal alanine and arginine. The activity of P. putida lup aminopeptidase is strongly inhibited in the presence of specific metallopeptidase inhibitors and is partly recovered in the presence of Zn2+ and Co2+ ions. Co2+, Mg2+ and Ca2+ ions increased the activity of the enzyme. Moreover, the enzyme was inhibited by inhibitors of cysteine enzymes. Analysis of fragments of the amino acid sequence of the purified enzyme demonstrated high similarity to PepN of Pseudomonas putida GB-1.