Characterization of a novel zinc-containing, lysine-specific aminopeptidase from the hyperthermophilic archaeon Pyrococcus furiosus.

ABSTRACT: Cell extracts of the proteolytic, hyperthermophilic archaeon Pyrococcus furiosus contain high specific activity (11 U/mg) of lysine aminopeptidase (KAP), as measured by the hydrolysis of L-lysyl-p-nitroanilide (Lys-pNA). The enzyme was purified by multistep chromatography. KAP is a homotetramer (38.2 kDa per subunit) and, as purified, contains 2.0 +/- 0.48 zinc atoms per subunit. Surprisingly, its activity was stimulated fourfold by the addition of Co2+ ions (0.2 mM). Optimal KAP activity with Lys-pNA as the substrate occurred at pH 8.0 and a temperature of 100 degrees C. The enzyme had a narrow substrate specificity with di-, tri-, and tetrapeptides, and it hydrolyzed only basic N-terminal residues at high rates. Mass spectroscopy analysis of the purified enzyme was used to identify, in t

SUBMITTER: Story SV 

PROVIDER: S-EPMC1064047 | biostudies-literature | 2005 Mar

REPOSITORIES: biostudies-literature