title: A grey mullet enzyme displaying both lipase and phospholipase activities: purification and characterization.
abstract: A lipase from the golden grey mullet viscera was purified to homogeneity by ammonium sulphate precipitation, gel filtration, anionic and cation exchange chromatographies. The pure enzyme tentatively named grey mullet digestive lipase (GmDL) is a monomer having a molecular mass of about 35 kDa, as determined by SDS-PAGE analysis. No similarity was found between the NH2-terminal amino acid residues of GmDL and those of other known digestive lipases. GmDL is a serine enzyme, like all known lipases from different origins. Interestingly, GmDL has not only lipase activity but also a phospholipase activity which requires the presence of Ca(2+) and bile salts. Specific activities of 64 U/mg, 55 U/mg and 63 U/mg were measured using tributyrin, olive oil emulsion or phosphatidylcholine as substrate, respectively at pH 8 and at 50°C. GmDL is therefore a thermo-active enzyme as compared to other fish lipases studied so far. It is worth to notice that grey mullet lipase was active in the presence of salt concentrations as high as 0.8M.
authors.affiliation: Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS route de Soukra, 3038 Sfax, Tunisia.
authors.forename: Nabil
authors.initials: N
authors.lastname: Smichi
authors.forename: Youssef
authors.initials: Y
authors.lastname: Gargouri
authors.forename: Nabil
authors.initials: N
authors.lastname: Miled
authors.forename: Ahmed
authors.initials: A
authors.lastname: Fendri
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D057075:Enzyme Assays; D004795:Enzyme Stability; D029941:Fish Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D007783:Lactones / Q000737:chemistry; D008049:Lipase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D008066:Lipolysis; D000069463:Olive Oil; D000077403:Orlistat; D010713:Phosphatidylcholines / Q000737:chemistry; D010740:Phospholipases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D010938:Plant Oils / Q000737:chemistry; D020539:Sequence Analysis, Protein; D023701:Smegmamorpha
chemical_list: D001647:Bile Acids and Salts; D029941:Fish Proteins; D007783:Lactones; D000069463:Olive Oil; D010713:Phosphatidylcholines; D010938:Plant Oils; D000077403:Orlistat; D010740:Phospholipases; D008049:Lipase; D002118:Calcium