Galactolipids, mainly monogalactosyl diglycerides (MGDG) and digalactosyl diglycerides (DGDG, are the main lipids found in the membranes of plants, algae and photosynthetic microorganisms like microalgae and cyanobacteria. As such, they are the main lipids present at the surface of the earth.It was estimated they may represent up to 80 % of the fatty acid stocks, including a large proportion of polyunsaturated fatty acids (PUFA) like a -linolenic acid (ALA). Nevertheless, the interest in these lipids for nutrition and other applications remains limited, probably because they are dispersed in the biomass and are not as easy to extract as vegetable oils from oleaginous fruits and oil seeds.The development of galactolipase assays has led recently to the characterization of the enzymes involved in the digestion of galactolipids in the gastrointestinal tract. Pancreatic lipase-related protein 2 (PLRP2) has thus been identified as the main actor of galactolipid digestion in humans, together with pancreatic carboxyl esterase.The presence and expression of PLRP2 is particularly marked in monogastric herbivores thus highlighting the peculiar role of PLRP2 in the digestion of plant lipids. Similarly, pancreatic lipase homologs are found to be expressed in the midgut of in folivorous insects, in which a high galactolipase activity can be measured. Specific enzyme assays have also allowed to screening various microbial lipases for galactolipase activity. The cutinase from Fusarium solani was thus found to digest galactolipids at a high rate and this activity may be essential for the digestion of leaves by this fungal pathogen of plants.
We present here a review on the current knowledge on the structure-function relationships of galactolipases and their physiological role in the digestion of galactolipids and uptake of ALA and other long chain PUFAs.
Speaker Background: Frédéric Carrière is Director of Research at Centre National de la Recherche Scientifique (CNRS) and Director of the Laboratory of Enzymology at Interfaces and Physiology of Lipolysis. He has 25 years of expertise in the field of lipids and lipolytic enzymes and over 190 publications (h-index=39) dealing with the structure-function relationships and physiological roles of digestive lipase. Frédéric’s clinical work is used today for developing new lipases for enzyme replacement therapy, as well as in vitro methods for simulating digestion in vitro.
Further information: http://eipl.cnrs-mrs.fr/cv1.php?nom=carriere