title: Differential regulation of taurine biosynthesis in rainbow trout and Japanese flounder.
abstract: Animals have varied taurine biosynthesis capability, which was determined by activities of key enzymes including cysteine dioxygenase (CDO) and cysteine sulfinate decarboxylase (CSD). However, whether CDO and CSD are differentially regulated across species remains unexplored. In the present study, we examined the regulations of CDO and CSD in rainbow trout and Japanese flounder, the two fish species with high and low taurine biosynthesis ability respectively. Our results showed that the expression of CDO was lower in rainbow trout but more responsive to cysteine stimulation compared to that in Japanese flounder. On the other hand, both the expression and catalytic efficiency (k(cat)) of CSD were higher in rainbow trout than those of Japanese flounder. A three-residue substrate recognition motif in rainbow trout CSD with sequence of F126/S146/Y148 was identified to be responsible for high k(cat), while that with sequence of F88/N108/F110 in Japanese flounder led to low k(cat), as suggested by site-directed mutagenesis studies. In summary, our results determined new aspects of taurine biosynthesis regulation across species.
authors.affiliation: Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao 266003, PR China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao 266003, PR China.
authors.forename: Gen
authors.initials: G
authors.lastname: He
authors.affiliation: Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao 266003, PR China.
authors.forename: Kangsen
authors.initials: K
authors.lastname: Mai
authors.affiliation: Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao 266003, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao 266003, PR China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D050558:Cysteine Dioxygenase / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary; D004789:Enzyme Activation; D005432:Flounder / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D008099:Liver / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D013654:Taurine / Q000096:biosynthesis*
chemical_list: D018076:DNA, Complementary; D013654:Taurine; D050558:Cysteine Dioxygenase; D002262:Carboxy-Lyases; C019972:sulfoalanine decarboxylase