| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1184916 | Food Chemistry | 2013 | 9 Pages |
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.
► Freeze–thawing results in a drastic decrease in cellular PO activity. ► Hc-derived PO activity is retained after freeze–thawing. ► Hc-derived PO activity can be inhibited by known PO inhibitors. ► The nature of Hc-inhibitor interactions are discussed. ► Hc-derived PO activity contributes to hyperpigmentation in shellfish.
