title: In vitro alterations of L-asparaginase activity of Tetrahymena pyriformis by lipids.
abstract: A membrane-bound L-asparaginase (EC 3.5.1.1) of Tetrahymena pyriformis was purified to homogeneity. The purified enzyme is a lipoprotein, since it is inactivated by phospholipase C and its activity is restored by the addition of naturally occurring lipids, such as phosphatidylcholine, triolein and oleyl acetate. The relative effectiveness of a variety of phospholipids, free saturated and unsaturated fatty acids, or neutral lipids, such as esters of fatty acids and glycerides, with respect to the activation of purified L-asparaginase is compared. Enzyme activity is reconstituted in the presence of lipids and evidence for the formation of an enzyme-phospholipid complex is presented. The data of this report suggest that L-asparaginase may have a requirement for lipids that reconstitute a physiological hydrophobic environment, similar to the one existing in vivo.
mesh_terms: D000818:Animals; D001215:Asparaginase / Q000302:isolation & purification / Q000378:metabolism*; D066298:In Vitro Techniques; D008055:Lipids / Q000494:pharmacology*; D010743:Phospholipids / Q000494:pharmacology*; D013769:Tetrahymena pyriformis / Q000187:drug effects / Q000201:enzymology*
chemical_list: D008055:Lipids; D010743:Phospholipids; D001215:Asparaginase