Purification and Biochemical Characterization of Lipase from Ficus carica Latex of Tunisian East Coast Zidi Variety

Lipase from Ficus carica L. (Moraceae) latex of the Zidi variety was purified 80.5-fold with 68.5 % recovery using silica gel chromatography. The molecular weight of the enzyme was 29 kDa as determined by SDS-PAGE. High lipolytic activity was found in the crude extract during the fruit ripening process. The activity of purified lipase (ZL) seemed to depend strongly on chain length and showed a preference to long chain triacylglycerols. Indeed, ZL specific activity was 370.3 UI/mg using olive oil as a substrate at 45 °C and pH 5.5. In contrast, activity towards short chain triacylglycerols (tributyrin) was 12-fold lower (32 UI/mg). The enzyme was quite stable in the pH range 4–8, and thermally stable at 60 °C displaying t 1/2 about 90 min using olive oil as a substrate. The values of K m app and V m were found to be 14.3 mM and 294.1 μmol/min/mg, respectively. ZL activity was strongly reduced by Fe2+, Mg2+ and Zn2+, while significantly increased by Ca2+ and Cu2+. The enzyme was stimulated by sodium dodecyl sulfate, and Tween-80, while Triton X-100 and EDTA had a slight inhibitory effect. No Effect was observed in addition of PMSF and iodoacetic acid.