Rousset A

References (2)

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

Title : The galactolipase activity of some microbial lipases and pancreatic enzymes - Amara_2013_Eur.J.Lipid.Sci.Technol_115_442
Author(s) : Amara S , Lafont D , Parsiegla G , Point V , Chabannes A , Rousset A , Carriere F
Ref : Eur J Lipid Sci Technol , 115 :442 , 2013
Abstract : Several well known microbial lipases were screened for their ability to hydrolyze synthetic medium chain monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). Fusarium solani cutinase and Thermomyces lanuginosus lipase (TLL) were found to hydrolyze MGDG at high rates (984 +/- 62 and 450 +/-41 U/mg, respectively). These activities remained however lower than those measured with pancreatic lipase-related protein 2 (PLRP2) on the same substrate. As previously observed with PLRP2, galactolipid-bile salt mixed micelles were found to be the best substrate form for microbial enzymes. The galactolipid to bile salt molar ratios for measuring maximum galactolipase activities were found to be similar to those previously established with PLRP2, suggesting that bile salts have mainly an effect on the substrate and not on the enzyme itself. The galactolipase activity of cutinase and TLL, as well as human and guinea pig PLRP2s were also measured using galactolipid monomolecular films. Enzymes having a lid (TLL and human PLRP2) were found to act at higher surface pressures than those with no lid (cutinase and guinea pig PLRP2). In silico docking of medium chain MGDG and DGDG in the active site of guinea pig PLRP2 and TLL reveals some structural analogies between these enzymes
ESTHER : Amara_2013_Eur.J.Lipid.Sci.Technol_115_442
PubMedSearch : Amara_2013_Eur.J.Lipid.Sci.Technol_115_442
Gene_locus related to this paper: bovin-balip , human-CEL