Melanosis in Penaeus monodon: Involvement of the Laccase-like Activity of Hemocyanin

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• 作者：Cédric Le Bris ; Benoit Cudennec ; Pascal Dhulster ; Djamel Drider ; Guillaume Duflos ; Thierry Grard
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：64
• 期：3
• 页码：663-670
• 全文大小：379K
• ISSN：1520-5118

文摘

In shrimp, the development of postmortem melanosis resulting from phenoloxidase activities leads to important economic losses. Phenoloxidase enzymes include catechol oxidases, laccases, and tyrosinases, but hemocyanin is also capable of phenoloxidase activities. These activities have been explored in Penaeus monodon, using different substrates. Results highlighted that tyrosinase-specific substrates were little oxidized, whereas hydroquinone (laccase-specific substrate) was more highly oxidized than l-DOPA (nonspecific substrate) in the pereopods and pleopods. Global phenoloxidase activity, assayed with l-DOPA, did not appear thermally stable over time and probably resulted from phenoloxidase enzymes. Conversely, the laccase-like activity assayed with hydroquinone was thermally stable over time, reflecting the thermal stability of hemocyanin. Independently of the anatomical compartment, the temperature, or the substrate, the highest activities were assayed in the cuticular compartments. This study demonstrates the complexity of phenoloxidase activities in P. monodon, and the importance of considering all the activities, including laccase-like activities such as that of hemocyanin.