Acetylcholinesterase in the sea urchin Lytechinus variegatus: characterization and developmental expression in larvae.
Acetylcholinesterase (AChE) in the echinoid Lytechinus variegatus has been characterized. Kinetic parameters V(max), K(m), K(ss), and b were 2594+/-1048 nmol ATCh hydrolyzed/min/mg tissue wet weight, 185+/-11 microM, 308+/-100 mM, and 0.2, respectively for the substrate ATCh and 17.8+/-6.87 nmol BTCh hydrolyzed/min/mg tissue wet weight, 654+/-424 microM, 36+/-31 mM, and 0.6, respectively for BTCh. Pharmacologic analyses were performed with four inhibitors of cholinesterases, physostigmine, BW284c51, ethopropazine, and iso-OMPA, and yielded IC(50) values of 106+/-4 nM, 718+/-118 nM, 2.57+/-0.6 mM, and >0.0300 M, respectively. Both kinetic and pharmacologic results confirmed the existence of AChE in larval L. variegatus. Dimeric and tetrameric globular forms (determined by velocity sedimentation on sucrose gradients) were present in L. variegatus larvae. Activity of AChE increased significantly as larvae progressed in development from embryos to eight-arm larvae. Acetylcholinesterase activity of F1 larvae derived from sea urchins collected from wild populations and of F1 larvae derived from sea urchins cultured in the laboratory and fed two different diets suggest that the nutritional and/or environmental history of the adult sea urchin affect the developmental progression of AChE activity in the F1 offspring.
Jennings
Natalie A
NA
Department of Biology, The University of Alabama at Birmingham, 1300 University Blvd., Birmingham, Alabama 35294-1170, USA. najennin@samford.edu
Pezzementi
Leo
L
Lawrence
Addison L
AL
Watts
Stephen A
SA
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002219:Carbamates / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000201:enzymology; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D007700:Kinetics; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D047331:Lytechinus / Q000187:drug effects / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development*; D010755:Organophosphates / Q000494:pharmacology; D013379:Substrate Specificity / Q000187:drug effects
D002219:Carbamates; D002800:Cholinesterase Inhibitors; D007527:Isoenzymes; D010755:Organophosphates; D000110:Acetylcholinesterase