With some exceptions, oilseed lipases are generally
more active with triacylglycerols containing short chain
fatty acids. Commonly used substrates include
commercially produced plant oils with unknown purity
and non-specific polluting agents, triacylglycerols with
short chain fatty acids such as acetic and butyric acids,
saturated and non-saturated acylglycerols and
fluorescent substrates with molecular structures
composed of monoesters (Borgston and Borckman,
1984; Enujiagha et al., 2004).
According to Hellyer et al. (1999), seed lipases
show selectivity for the dominant fatty acids in the
seed. For example, castor bean lipases show
selectivity for triricinolein; palm tree lipase for
tricaproin or trilaurein; elm lipase for tricaproin and
Vermonia sp. lipase for trivernolein. Other seed
lipases can quickly hydrolyze a great variety of fatty
acids, such as canola and pinus seed lipases. Canola
seed lipase usually presents activity with most lipids,
but discriminates fatty acids with cis-4 or cis-6
double-bonds.
Tables 1 and 2 show the hydrolysis of several
triacylglycerols and of synthetic 4-methyl-
umbelliphenyl substrates, respectively, by seed
lipases.