Abstract: Phenylalanine ammonia-lyase (PAL) was isolated and purified from lily (Lilium davidii var. unicolor) bulbs via precipitating with ammonium sulphate grading from 40% to 75% and DEAE-Sepharose ion-exchange chromatography techniques. A 13.19-fold purification with a yield of 4.68% was obtained. The subunit molecular weight was estimated as 58.7 kD by SDS-PAGE. Results of studies on zymological properties indicated that PAL in the lily bulbs was not able to endure acid and alkali, especially the former. The PAL activity declined gradually along with the increasing of temperature and prolonging of bath duration, however it still remained 47% after 30 min at 40 ℃. This revealed that 40 ℃ was the optimum bath temperature. PAL had a Km of 4.1×10^-3 mol·L^-1 for L-Phenylalanine at 40 ℃. Ions such as Mn²⁺, Fe²⁺, Cu²⁺ and Fe³⁺ enhanced the PAL activity and 1.0, 1.0, 2.0 and 1.0 mmol·L^-1 were the most effective respectively within the tested concentrations. Ag⁺, Co²⁺ and Ca²⁺inhibited the PAL activity and the impact of Ag⁺ was the severest.

Key words: Lilium davidii var. unicolor, bulb, PAL, purification, zymological properties