凡纳滨对虾血蓝蛋白酚氧化酶活性的研究  

The Phenoloxidase Activity of Hemocyanin from White Leg Shrimp Litopenaeus vannamei

作　　者：严芳[1] 章跃陵[1] 罗活强[1] 胡忠[1] 黄通旺[1] 叶向群[2] 

机构地区：[1]汕头大学理学院,广东汕头515063 [2]汕头大学医学院第一附属医院,广东汕头515041

出　　处：《水产科学》2008年第1期5-8,共4页Fisheries Science

基　　金：国家自然科学基金资助项目(30400258);广东省自然科学基金资助项目(06027212);汕头市科技计划项目(2006-148)

摘　　要：试验结果表明,凡纳滨对虾血蓝蛋白在胰蛋白酶诱导下可表现出一定的酚氧化酶活性,与对照组相比,其酚氧化酶活力单位显著上升。同时,其活性可被D-半乳糖、α-葡萄糖、蔗糖、麦芽糖、甘露醇和N-乙酰神经氨酸不同程度地抑制,其抑制率分别为67%、100%、33%、33%、67%和100%。血蓝蛋白与胰蛋白酶孵育后经SDS-PAGE分析和L-Dopa显色,其75 kDa单体呈明显的棕褐色,添加抑制剂N-乙酰神经氨酸之后,其显色强度显著减弱。由此进一步证实凡纳滨对虾血蓝蛋白在胰蛋白酶诱导下确实具有酚氧化酶活性,其活性可被不同的糖所抑制,其发挥活性的单体为75 kDa单体。It has been approved that hemocyanin is a kind of multi-functional protein, particularly it could be functionally converted into phenoloxidase by some reagents recently. However, to date no research about white leg shrimp Litopenaeus vannamei hemocyanin showing phenoloxidase activity was reported. Thus in the paper, an attempt was made to research the phenoloxidase activity in the shrimp hemocyanin, its influencing factors and active region. The methods of affinity chromatography, SDS-PAGE, Western-blotting and identification of phenoloxidase activity with A490. and L-Dopa staining were used. The results showed that the shrimp hemocyanin expressed phe- noloxidase activity, whose A490,m increased after being activated by trypsin. And the phenoloxidase activity unit in the experimental groups was 13 times more than that in the control group. At the same time, its phenoloxidase activity was inhibited by 6 types of saccharides including D-galactose （ 8.5 mmol/L）, α-glucose （ 8.5 mmol/L）, sucrose （8.5 mmoL/L）, maltose （8.5 mmoL/L） , mannitol （8.5 mmol/L） and N-acetylneuraminic acid （0. 15 mmol/L）, at a rate of 67%, 100% ,33% ,33% ,67% and 100% respectively. Specially, the hemocyanin subunit with 75 kDa was stained strongly after hemocyanin reacted with trypsin using the methods of SDS-PAGE and L-Dopa staining. Moreover, when the inhibitor of N-acetylneuraminic acid was added to the reactive system, its staining degree was weakened accordingly. Therefore, our results indicated that the shrimp hemocyanin possessed phenoloxidase activity,which could be inhibited by some saccharide, and its active region was located in its 75 kDa subunit.

关 键 词：凡纳滨对虾 血蓝蛋白 酚氧化酶活性 糖 活性区域 

分 类 号：S968.22[农业科学—水产养殖]