Sahaka M

References (3)

Title : Quantitative monitoring of galactolipid hydrolysis by pancreatic lipase-related protein 2 using thin layer chromatography and thymol-sulfuric acid derivatization - Sahaka_2021_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1173_122674
Author(s) : Sahaka M , Amara S , Lecomte J , Rodier JD , Lafont D , Villeneuve P , Gontero B , Carriere F
Ref : Journal of Chromatography B Analyt Technol Biomed Life Sciences , 1173 :122674 , 2021
Abstract : Galactolipids are the most abundant lipids on earth where they are mainly found in photosynthetic membranes of plant, algae, and cyanobacteria. Pancreatic lipase-related protein 2 (PLRP2) is an enzyme with galactolipase activity allowing mammals, especially herbivores, to digest this important source of fatty acids. We present a method for the quantitative analysis of galactolipids and galactosylated products resulting from their digestion by guinea pig PLRP2 (GPLRP2), using thin-layer-chromatography (TLC), thymol-sulfuric acid as derivatization reagent and scanning densitometry for detection. Thymol-sulfuric acid reagent has been used for the colorimetric detection of carbohydrates. It is shown here that the derivatization of galactosyl group from galactolipids by this reagent is not affected by the bound acyl glycerol, acyl chains length and number of galactose residues in the polar head. This allowed quantifying simultaneously the initial substrate and all galactosylated products generated upon the hydrolysis of monogalactosyl di-octanoylglycerol (C8-MGDG) by GPLRP2 using a single calibration with C8-MGDG as reference standard. The reaction products, monogalactosyl monooctanoyl glycerol (C8-MGMG) and monogalactosyl glycerol (MGG), were identified and quantified, MGG being recovered from the aqueous phase and analyzed by a separate TLC analysis. This method is therefore suitable to quantify the products resulting from the release of both fatty acids present in MGDG and thereby shows that PLRP2 can contribute to the complete digestion of galactolipids and further intestinal absorption of their fatty acids.
ESTHER : Sahaka_2021_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1173_122674
PubMedSearch : Sahaka_2021_J.Chromatogr.B.Analyt.Technol.Biomed.Life.Sci_1173_122674
PubMedID: 33827017

Title : The digestion of galactolipids and its ubiquitous function in Nature for the uptake of the essential alpha-linolenic acid - Sahaka_2020_Food.Funct_11_6710
Author(s) : Sahaka M , Amara S , Wattanakul J , Gedi MA , Aldai N , Parsiegla G , Lecomte J , Christeller JT , Gray D , Gontero B , Villeneuve P , Carriere F
Ref : Food Funct , 11 :6710-6744 , 2020
Abstract : Galactolipids, mainly monogalactosyl diglycerides and digalactosyl diglycerides 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 earth. They may represent up to 80% of the fatty acid stocks, including a large proportion of polyunsaturated fatty acids mainly alpha-linolenic acid (ALA). Nevertheless, the interest in these lipids for nutrition and other applications remains overlooked, probably because they are dispersed in the biomass and are not as easy to extract as vegetable oils from oleaginous fruit and oil seeds. Another reason is that galactolipids only represent a small fraction of the acylglycerolipids present in modern human diet. In herbivores such as horses, fish and folivorous insects, galactolipids may however represent the main source of dietary fatty acids due to their dietary habits and digestion physiology. The development of galactolipase assays has led to the identification and characterization of the enzymes involved in the digestion of galactolipids in the gastrointestinal tract, as well as by microorganisms. Pancreatic lipase-related protein 2 (PLRP2) has been identified as an important factor of galactolipid digestion in humans, together with pancreatic carboxyl ester hydrolase (CEH). The levels of PLRP2 are particularly high 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 folivorous insects, in which a high galactolipase activity can be measured. In fish, however, CEH is the main galactolipase involved. This review discusses the origins and fatty acid composition of galactolipids and the physiological contribution of galactolipid digestion in various species. This overlooked aspect of lipid digestion ensures not only the intake of ALA from its main natural source, but also the main lipid source of energy for growth of some herbivorous species.
ESTHER : Sahaka_2020_Food.Funct_11_6710
PubMedSearch : Sahaka_2020_Food.Funct_11_6710
PubMedID: 32687132
Gene_locus related to this paper: helam-a0a2w1b5z2 , cavpo-2plrp

Title : Galactolipase activity of Talaromyces thermophilus lipase on galactolipid micelles, monomolecular films and UV-absorbing surface-coated substrate - Belhaj_2018_Biochim.Biophys.Acta.Mol.Cell.Biol.Lipids_1863_1006
Author(s) : Belhaj I , Amara S , Parsiegla G , Sutto-Ortiz P , Sahaka M , Belghith H , Rousset A , Lafont D , Carriere F
Ref : Biochimica & Biophysica Acta Molecular & Cellular Biology Lipids , 1863 :1006 , 2018
Abstract : Talaromyces thermophilus lipase (TTL) was found to hydrolyze monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG) substrates presented in various forms to the enzyme. Different assay techniques were used for each substrate: pHstat with dioctanoyl galactolipid-bile salt mixed micelles, barostat with dilauroyl galactolipid monomolecular films spread at the air-water interface, and UV absorption using a novel MGDG substrate containing alpha-eleostearic acid as chromophore and coated on microtiter plates. The kinetic properties of TTL were compared to those of the homologous lipase from Thermomyces lanuginosus (TLL), guinea pig pancreatic lipase-related protein 2 and Fusarium solani cutinase. TTL was found to be the most active galactolipase, with a higher activity on micelles than on monomolecular films or surface-coated MGDG. Nevertheless, the UV absorption assay with coated MGDG was highly sensitive and allowed measuring significant activities with about 10ng of enzymes, against 100ng to 10mug with the pHstat. TTL showed longer lag times than TLL for reaching steady state kinetics of hydrolysis with monomolecular films or surface-coated MGDG. These findings and 3D-modelling of TTL based on the known structure of TLL pointed out to two phenylalanine to leucine substitutions in TTL, that could be responsible for its slower adsorption at lipid-water interface. TTL was found to be more active on MGDG than on DGDG using both galactolipid-bile salt mixed micelles and galactolipid monomolecular films. These later experiments suggest that the second galactose on galactolipid polar head impairs the enzyme adsorption on its aggregated substrate.
ESTHER : Belhaj_2018_Biochim.Biophys.Acta.Mol.Cell.Biol.Lipids_1863_1006
PubMedSearch : Belhaj_2018_Biochim.Biophys.Acta.Mol.Cell.Biol.Lipids_1863_1006
PubMedID: 29859246
Gene_locus related to this paper: talth-f6lqk7