title: A novel hepatopancreatic phospholipase A2 from Hexaplex trunculus with digestive and toxic activities.
abstract: A marine snail digestive phospholipase A2 (mSDPL) was purified from delipidated hepatopancreas. Unlike known digestive phospholipases A2, which are 14 kDa proteins, the purified mSDPL has a molecular mass of about 30 kDa. It has a specific activity of about 180 U/mg measured at 50 degrees C and pH 8.5 using phosphatidylcholine liposomes as a substrate in the presence of 4 mM NaTDC and 6mM CaCl2. The N-terminal amino-acid of the purified mSDPL does not share any homology with known phospholipases. Moreover, the mSDPL exhibits hemolytic activity in intact erythrocytes and can penetrate phospholipid monolayers at high surface pressure, comparable to snake venom PLA2. These observations suggest that mSDPL could be toxic to mammal cells. However, mSDPL can be classified as a member of a new family of enzymes. It should be situated between the class of toxic phospholipase A2 from venoms and another class of non toxic pancreatic phospholipase A2 from mammals.
authors.affiliation: Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS, BPW 1173, Sfax, Tunisia.
authors.forename: Zied
authors.initials: Z
authors.lastname: Zarai
authors.forename: Abir Ben
authors.initials: AB
authors.lastname: Bacha
authors.forename: Habib
authors.initials: H
authors.lastname: Horchani
authors.forename: Sofiane
authors.initials: S
authors.lastname: Bezzine
authors.forename: Nacim
authors.initials: N
authors.lastname: Zouari
authors.forename: Youssef
authors.initials: Y
authors.lastname: Gargouri
authors.forename: Hafedh
authors.initials: H
authors.lastname: Mejdoub
mesh_terms: D000595:Amino Acid Sequence; D000645:Ammonium Sulfate / Q000737:chemistry; D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D005591:Chemical Fractionation; D011232:Chemical Precipitation; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004063:Digestion; D004795:Enzyme Stability; D049851:Gastropoda / Q000201:enzymology* / Q000502:physiology; D006461:Hemolysis / Q000187:drug effects; D043143:Hepatopancreas / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D054467:Phospholipases A2 / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000633:toxicity*; D011817:Rabbits; D051381:Rats; D012621:Seasons; D013379:Substrate Specificity; D013499:Surface Properties; D013696:Temperature; D014357:Trypsin / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D054467:Phospholipases A2; D014357:Trypsin; D000645:Ammonium Sulfate; D002118:Calcium