title: Effects of known phenoloxidase inhibitors on hemocyanin-derived phenoloxidase from Limulus polyphemus.
abstract: Inhibitors of phenoloxidase are used routinely to characterise the structural and functional properties of phenoloxidases. Hemocyanin-derived phenoloxidase activity is also sensitive to standard phenoloxidase inhibitors. In this study, we characterise the effects of a number of phenoloxidase inhibitors on hemocyanin-derived phenoloxidase activity from the chelicerate, Limulus polyphemus. Both inhibition type and K(i) values were similar to those observed for hemocyanin-derived phenoloxidase from another chelicerate, Eurypelma californicum. In addition, substrate inhibition was observed at concentrations above 2mM dopamine. The conformation in which two of the inhibitors, namely tropolone and kojic acid, would bind near the Cu(II) centre of hemocyanin is proposed.
authors.affiliation: Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
authors.forename: Jamie
authors.initials: J
authors.lastname: Wright
authors.forename: William McCaskill
authors.initials: WM
authors.lastname: Clark
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Cain
authors.forename: Alan
authors.initials: A
authors.lastname: Patterson
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Coates
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Nairn
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002614:Chelating Agents / Q000378:metabolism / Q000494:pharmacology*; D003300:Copper / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D006433:Hemocyanins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D006604:Hexylresorcinol / Q000378:metabolism / Q000494:pharmacology; D006737:Horseshoe Crabs / Q000201:enzymology*; D007700:Kinetics; D008958:Models, Molecular; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010670:Phenylthiourea / Q000378:metabolism / Q000494:pharmacology; D011487:Protein Conformation; D011753:Pyrones / Q000378:metabolism / Q000494:pharmacology; D014334:Tropolone / Q000378:metabolism / Q000494:pharmacology
chemical_list: D002614:Chelating Agents; D004791:Enzyme Inhibitors; D011753:Pyrones; D010670:Phenylthiourea; C011890:kojic acid; D003300:Copper; D014334:Tropolone; D006433:Hemocyanins; D014442:Monophenol Monooxygenase; D006604:Hexylresorcinol; D004298:Dopamine