As indicated inTable 1, copper ions at 2mMshowed an inhibitory
effect (about 75%) on the olive oil lipase. A similar effect of Cu2þ was
reported for Oryza sativa lipase [2]. It should be noted that Cu2þ is
the most commonly used pesticide in olive tree fields, so it is of great
interest to know its effects on olive lipid metabolism. The olive oil
lipase activity was marginally affected by the presence of mercury
chloride, which is considered a serine modifier because it reacts
with sulfhydryl groups, whereas 0.1e0.5 mM HgCl2 reduced to less
of 17% [9] and even completely inhibited castor bean acid lipase
activity [34], moreover 0.15 mM HgCl2 determined the complete
inhibition of peanut lipase [41]. Therefore, our results suggest
that olive fruit lipase does not require Ser in the catalytic site.