S. Vaz et al., Lipase-catalyzed fatty acid exchange in digalactosyldiacylglycerol. Improvement of yield due to the addition of phenylboronic acid, BIOCATAL B, 18(1), 2000, pp. 1-12
Rhizopus arrhizus lipase immobilized on porous polypropylene was used in an
acidolysis reaction in toluene at low water activity (0.11) to exchange th
e fatty acid in the sn-l-position of digalactosyldiacylglycerol (DGDG). Wit
hout extra precautions, an yield of only about 20% was obtained, mainly due
to side reactions; incorporation of an extra acyl group on the primary hyd
roxyl of the digalactosyl moiety and acyl migration in partially deacylated
reaction intermediates, followed by further hydrolysis. By the addition of
phenylboronic acid (equimolar amount with respect to DGDG) both the side r
eactions were suppressed and the yield of DGDG containing the new fatty aci
d (heptadecanoic acid) in the sn-l-position increased to about 60%.