title: Partial characterization of a lipase from gypsy moth (lymantria dispar L.) larval midgut.
abstract: Lipase activity of the gypsy moth (Lymantria dispar L.) was studied by the spectrophotometric method using crude homogenate of fifth-instar larval midgut tissues as the enzyme source and p-nitrophenyl caprylate (pNPC) as substrate. A Km value of 0.310 mM and a Vmax value of 1.479 U/mg prot. were obtained for this substrate. Among various p-nitrophenyl esters tested, maximum activity was obtained for p-nitrophenyl caprylate and p-nitrophenyl caprate. The enzyme was most active at alkaline pH, with maximum at pH 8.2. Decreased activity was detected after preincubation in buffers of pH below 7.0 and above 8.2. The enzyme was unstable at room temperature. The enzyme was Ca2+ independent. Its activity was inhibited by PMSF, Fe2+, Ag+ and Pb2+, while Fe3+ inhibited enzyme activity by about 40%.
authors.affiliation: Institute for Biological Research, Despot Stefan Blvd. 142, l1000 Belgrade, Serbia. mm1507@ibiss.bg.ac.yu
authors.forename: Marija
authors.initials: M
authors.lastname: Mrdaković
authors.forename: Jelica
authors.initials: J
authors.lastname: Lazarević
authors.forename: Vesna
authors.initials: V
authors.lastname: Perić-Mataruga
authors.forename: Larisa
authors.initials: L
authors.lastname: Ilijin
authors.forename: Milena
authors.initials: M
authors.lastname: Vlahović
mesh_terms: D000818:Animals; D002210:Caprylates; D004064:Digestive System / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007814:Larva / Q000201:enzymology; D008049:Lipase / Q000378:metabolism*; D009036:Moths / Q000201:enzymology*; D055771:Serbia; D013053:Spectrophotometry; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002210:Caprylates; C034106:4-nitrophenyloctanoate; D008049:Lipase