Isolation and Biochemical Characteristics Analyses of Phenoloxidases (POs) in Three Cultured Mollusk Species  

作　　者：SONG Xiangdi JIANG Jingwei XING Jing ZHAN Wenbin 

机构地区：[1]Laboratory of Pathology and Immunology of Aquatic Animals,KLMME,Ocean University of China,Qingdao 266003,China [2]Laboratory for Marine Fisheries Science and Food Production Processes,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266235,China

出　　处：《Journal of Ocean University of China》2022年第2期465-472,共8页中国海洋大学学报（英文版）

基　　金：supported by the Qingdao National La-boratory for Marine Science and Technology(No.QNLM 2016ORP0307);the National Key Research and Develop-ment Program of China(No.YFD0900504);the National Basic Research Program of China(No.2012CB114405);the Taishan Scholar Program of Shandong Province.

摘　　要：Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk species,including scallop Chla-mys farreri,abalone Haliotis discus hannai and clam Scapharca subcrenata.The POs were isolated from hemocytes using linear-gradient native-PAGE combined with catechol staining.The PO activities and their characters were investigated.The molecular mass of PO in C.farreri was 576 kDa,and it was 228 kDa in H.discus hannai.In S.subcrenata,four POs were detected and their mole-cular masses were 391 kDa,206 kDa,174 kDa and<67 kDa,which were named as 391-PO,206-PO,174-PO and s-PO,respectively.Ki-netic analyses indicated that all of the POs,except for 391-PO had higher affinity to L-DOPA and catechol than to hydroquinone and dopamine.However,all of the POs failed to oxidize tyrosine.The effects of divalent metal ions on POs’activities were assayed,in-cluding Fe^(2+),Mg^(2+),Zn^(2+),Mn^(2+),Cu^(2+)and Ca^(2+)from FeCl_(2),MgSO_(4),ZnSO_(4),MnCl_(2),CuSO_(4)and CaCl_(2).The POs were inhibited by Fe^(2+)at all determined concentrations.Additionally,the inhibition assay showed that all of the POs were inhibited by cysteine,ascorbic acid,sodium sulfite,citric acid,ethylenediaminetetraacetic acid disodium(EDTA)and sodium diethyldithiocarbamate(DETC).The inhibition effects of critric acid and EDTA are dose-dependent.H.discus hannai PO and 391-PO were slightly inhibited by sodium azide,and H.discus hannai PO,391-PO and 174-PO were slightly inhibited by thiourea.In conclusion,the POs in the three cultured mollusks are copper-containing laccase-type phenoloxidases with similar biochemical characteristics even though their molecular masses are different.

关 键 词：Chlamys farreri Haliotis discus hannai Scapharca subcrenata PHENOLOXIDASE divalent metal ions INHIBITORS 

分 类 号：S917.4[农业科学—水产科学]