Purification and Biochemical Characterization of Lipase from Tunisian Euphorbia peplus Latex

Lipases from vegetable sources have been the focus of intense and growing research. The use of enzymes from plants has the advantage of employing industrial waste products. The lipase activity of Euphorbia peplus L. (Euphorbiaceae) was investigated for the first time. The Euphorbia peplus latex lipase (EpLL) was purified after ammonium sulfate fractionation and anion exchange chromatography on a DEAE-Cellulose column leading to 12.57-fold purification. The EpLL displayed a probable molecular weight of about 40 kDa. The lipase activity was optimum at a temperature of 40 A degrees C and pH 8, the specific activities of EpLL were found to be 249 +/- A 12.45 and 161.4 +/- A 8.07 U/mg when tributyrin (TC4) and olive oil were used as substrate respectively. The enzyme retained 80 % of its activity when incubated for 1 h at 50 A degrees C. The EpLL was strongly destabilised by divalent metal ions (Fe2+, Mg2+, Zn2+ and Cu2+). Lipase was slightly stimulated by Triton X-100 and Tween-80, while strongly inhibited by sodium dodecyl sulfate. A good stability of the enzyme in the presence of organic solvents was reveled suggesting its industrial utility.