Purification and some properties of ɛ-poly-l-lysine-degrading enzyme from Kitasatospora sp. CCTCC M205012

An ɛ-poly-l-lysine-degrading enzyme (PLD) from Kitasatospora sp. CCTCC M205012 has been purified to homogeneity by three steps of anion-exchange chromatography including DEAE-Sepharose, Source 15Q and Mono Q, with a 500-fold increase in specific activity and 40.9% yield. The PLD has a molecular mass of approximately 87.0 kDa and consists of two identical subunits with a molecular mass of 43.6 kDa. Electrophoretic shows that the PLD isoelectric point was about 7.2. The optimum temperature and pH for the PLD was 30 °C and 7.0, respectively. The PLD was deactivated by EDTA, which was indicated that the enzyme was a metallo enzyme. The activity of PLD was stimulated by Co2+ and inhibited by Ca2+ remarkably. The apparent Km with l-lysyl-p-nitroanilide as substrate was 0.216 mM and the Vmax was 0.112 mmol/min mg. The PLD was an exo-type enzyme and monomers of l-lysine were detected during the enzymatic degradation of ɛ-PL.