Department of Plant Protection, College of Agriculture, University of Guilan-Rasht, 41635-1314, Iran.
Comp Biochem Physiol B Biochem Mol Biol. 2011 Jan;158(1):117-23. doi: 10.1016/j.cbpb.2010.10.006. Epub 2010 Oct 20.
Insects protect themselves from microbial invaders by two main immune activities, namely the cellular and humoral reactions. Phenoloxidases are oxidative enzymes that have an important role in both cell-mediated and humoral immunity. In this study, the purification and biochemical characterization of a phenoloxidase from the hemocytes of the Sunn pest Eurygaster integriceps Puton (Hemiptera: Scutelleridae) were carried out. After the final purification step, the enzyme was purified 7.31-fold with a recovery of 3.94% and a specific activity of 4.95U/mg protein. Results of the biochemical characterization showed that the purified phenoloxidase has a maximum activity at pH 6 and at 30-35°C and is stable for 24-36h. Divalent cations such as Ca(2+) and Cu(2+) significantly increased the enzymatic activity and synthetic inhibitors such as phenylthiourea significantly decreased it. The purified phenoloxidase has a molecular mass of 22kDa. The current paper represents a further step towards the characterization of humoral immunity of E. integriceps in order to develop new strategies for the biological control of the Sunn pest.
昆虫通过两种主要的免疫活动来保护自己免受微生物入侵，即细胞和体液反应。酚氧化酶是一种氧化酶，在细胞介导和体液免疫中都具有重要作用。本研究对来自 Sunn 害虫 Eurygaster integriceps Puton（半翅目：Scutelleridae）血细胞中的酚氧化酶进行了纯化和生化特性分析。在最后的纯化步骤后，酶的纯化倍数为 7.31，回收率为 3.94%，比活为 4.95U/mg 蛋白。生化特性分析的结果表明，纯化的酚氧化酶在 pH6 和 30-35°C 时具有最大活性，并且在 24-36 小时内稳定。二价阳离子如 Ca(2+)和 Cu(2+)显著增加了酶的活性，而合成抑制剂如苯硫脲则显著降低了酶的活性。纯化的酚氧化酶的分子量为 22kDa。本研究进一步阐述了 E. integriceps 体液免疫的特性，以期为 Sunn 害虫的生物防治开发新策略。
