title: Kinetic and toxicological characteristics of acetylcholinesterase from the gills of oysters (Crassostrea rhizophorae) and other aquatic species.
abstract: The aim of this work was to characterize the cholinesterases from gills of Crassostrea rhizophorae in order to use them as biomarkers. Gills were homogenized and then centrifuged (9,000 x g, 4 degrees C, 30 min). S9 and Triton X-100 S9 treated (TX S9) fractions were employed as enzyme source. Km(ap) and Vmax were estimated, using acetylthiocholine iodide as substrate. Inhibition assays were performed with iso-OMPA and eserine. The Km(ap) for S9 and TX S9 fractions were 0.05 and 0.06 mM, whereas the Vmax were 1.92 and 5.84 nmol/min/mg protein. respectively. No inhibition was detected when the samples were incubated with iso-OMPA, suggesting the presence of acetylcholinesterases (AChE) in oyster gill homogenates. Sensitivity to eserine inhibition of AChE in the gills of oysters is intermediate when compared with other aquatic species.
authors.affiliation: Depto Ciências Fisiológicas, Fundação Universidade Federal de Rio Grande, RS, Brazil. jose@octopus.furg.br
authors.forename: J M
authors.initials: JM
authors.lastname: Monserrat
authors.forename: A
authors.initials: A
authors.lastname: Bianchini
authors.forename: A C D
authors.initials: AC
authors.lastname: Bainy
mesh_terms: D000110:Acetylcholinesterase / Q000494:pharmacology*; D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D005880:Gills / Q000201:enzymology*; D007700:Kinetics; D010125:Ostreidae / Q000502:physiology*; D010830:Physostigmine / Q000494:pharmacology; D012016:Reference Values
chemical_list: D015415:Biomarkers; D002800:Cholinesterase Inhibitors; D010830:Physostigmine; D000110:Acetylcholinesterase