Purification and characterization of an intracellular aminopeptidase from a wild strain of Lactobacillus plantarum isolated from traditional Serra da Estrela cheese

• Type: Article in International Scientific Journal
• Date: 2003

Authors

Macedo, AC (Author) Other; Tavares, TG (Author) Other; F. Xavier Malcata (Author) Other

Journal

Title: Enzyme and Microbial Technology

Vol. 32

Pages: 41-48

ISSN: 0141-0229

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 11 Citations

Scopus - 17 Citations

Other information

Authenticus ID: P-000-J2M

DOI: 10.1016/s0141-0229(02)00234-x

Abstract (EN): An intracellular hydrolase able to cleave L-lysine-p-nitroanilide was purified from Lactobacillus plantartar strain ESB5004 via two steps of precipitation with ammonium sulfate (at 30 and 50% (w/v)), followed by hydrophobic interaction and ion-exchange chromatographies. The aminopeptidase was purified up to 11-fold, with a final yield of ca. 1%. Its native molecular weight is ca. 70 kDa, and it is apparently composed of two subunits, the molecular weight of which is 34 kDa. The enzyme was assayed using a wide variety of p-nitroanilide (pNA) derivatives as substrates: it hydrolyzed preferentially pNA adducts of hydrophobic and basic amino acid residues; no hydrolysis was in particular observed of Glu-pNA, Gly-pNA or Pro-pNA. The enzyme activity was removed by the metal-chelating agent EDTA, thus suggesting that it is a metallo-enzyme; however, the EDTA-inhibited enzyme was reactivated in the presence of Co2+. Optimal aminopeptidase activity was obtained at 28degreesC (pH 7.0) and pH 6.5 (37degreesC). The enzyme was inhibited by 10 mM CaCl2 or MgCl2.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8