Two types of phenoloxidases contribute to hemolymph PO activity in spiny Lobster.
Two types of phenoloxidases contribute to hemolymph PO activity in spiny Lobster.
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两种酚氧化酶有助于龙虾血淋巴 PO 活性。
DOI：
10.1016/j.foodchem.2018.03.110
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发表时间：
2018
期刊：
影响因子：
8.8
通讯作者：
Haruhiko Toyohara
中科院分区：
文献类型：
--
作者：
Taro Masuda*;Tatsuki Kawauchi;Yuya Yata;Yasuyuki Matoba;Haruhiko Toyohara
酚氧化酶在甲壳动物的黑化过程中起着重要作用。在甲壳动物中至少有两种类型的PO：在血细胞中表达的常规类型（POα）和POβ，一种在肝胰腺中合成的分泌蛋白。我们调查了龙虾血淋巴中PO活性的来源，并测定了单PO和双PO活性的动力学参数。在龙虾血淋巴中，POα形成类似于POβ和血蓝蛋白的六聚体，对PO活性有贡献，而POβ的量很低。动力学分析表明，以酪胺和多巴胺为底物时，龙虾POα具有较高的速率常数，而虾POβ具有较高的专一性。甲壳动物血淋巴中至少存在两种PO分子，但优势PO分子类型因种而异。
Phenoloxidases (POs) play a crucial role in melanization of crustaceans. There are at least two types of POs characterized in crustaceans: the conventional type (POα here) that is expressed in hemocytes and POβ, a secreted protein synthesized in the hepatopancreas. We investigated the source of PO activity in the hemolymph of a lobster and determined the kinetic parameters of mono- and di-PO activities. In the lobster hemolymph, POα, which formed a hexamer similar to both POβ and hemocyanin, contributed to PO activity, whereas the amount of POβ was low. Kinetic analyses using purified prophenoloxidase of crustaceans showed that lobster POα has a higher rate constant, while shrimp POβ has higher specificity in both mono- and di-PO reactions, when tyramine and dopamine were employed as substrates. There should be at least two types of PO molecules in crustacean hemolymph, but the dominant PO molecule type varies among species.