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Updated: May 12, 2026

Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
Hemocyanin-derived phenoloxidase activity: a contributing factor to hyperpigmentation in Nephrops norvegicus
Christopher J Coates1, Jacqueline Nairn
1Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK. c.j.coates@stir.ac.uk
Abstract:
The phenomenon of hyperpigmentation (melanosis) in shellfish has long been attributed to phenoloxidase enzymes. Over the last number of years, the oxygen carrier hemocyanin, has demonstrated several immune- and physiological functionalities, most notably, inducible phenoloxidase activity. In this study, hemocyanin purified from the hemolymph of Nephrops norvegicus displays diphenoloxidase activity in the presence of a number of elicitors and retains structural and functional integrity throughout the process of freeze-thawing (at -25 °C). Conversely, cellular phenoloxidase activity (present in cell-lysates), demonstrates >98% reduction in activity after freeze-thawing. We present evidence that hemocyanin may act as a causative agent of hyperpigmentation in N. norvegicus. The inhibition of hemocyanin-derived phenoloxidase activity is discussed, and for the first time, the biophysical interactions of shellfish hemocyanin with known phenoloxidase inhibitors are presented.
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