Purification and properties of ε-poly-L-lysine-degrading enzyme from Kitasatospora sp.MY5-36

A ε-poly-L-lysine-degrading (PLD) enzyme from Kitasatospora sp.MY5-36 was purified and characterized. The enzyme was purified through three steps of anion exchange chromatography including DEAE-Sepharose, Source 15Q and Mono Q. The overall purification multiple was 500 with an enzymatic activity recovery rate of 40.7%. As detected by SDS-PAGE and gel filtration chromatography, the PLD enzyme of this strain was composed of two homogeneous subunits. The molecular weight of subunit and holoenzymes were 43.6 and 87.0 kDa, respectively. Its optimal pH value was 7.0 and the optimal temperature 30°C. The activity of PLD enzyme was kept stable when the enzyme was conserved in the temperature range from 20 to 40°C, however, it declined rapidly in the temperature range from 50 to 60°C. The K_m value was 0.216 mmol/L and the V_max 0.112 mmol/(L·min). The PLD enzyme is a kind of metalloenzymes, and can be activated by Co²⁺ and inhibited by Ca²⁺.