Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 2012-01-01

Effects of known phenoloxidase inhibitors on hemocyanin-derived phenoloxidase from Limulus polyphemus.

Jamie Wright, William McCaskill Clark, Jennifer A Cain, Alan Patterson, Christopher J Coates, Jacqueline Nairn

Index: Comp. Biochem. Physiol. B Biochem. Mol. Biol. 163(3-4) , 303-8, (2012)

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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.Copyright © 2012 Elsevier Inc. All rights reserved.