LAUSR

Abstract It is well known that the enzyme glucokinase (GK) plays an important role in the control of glucose homeostasis. In the present study, a glucokinase (To-GK) was cloned from golden pompano, Trachinotus ovatus . The To-GK cDNA is composed of 2151 bp with a 33 bp of 5′-UTR, 1437 bp open reading frame (ORF) and 681 bp 3′-UTR, encoding a polypeptide of 478 amino acids (GenBank accession no: ALX36181.1 ). Phylogenetic analysis revealed that To-GK showed highest similarity to Cynoglossus semilaevis GK. Tissue distribution analysis showed that the highest expression of the To-GK was detected in liver. Then, 8-week feeding trial was conducted to investigate the effects of dietary carbohydrate levels (57.5, 120.4, and 277.7 g kg − 1 ) on the activity and mRNA expression of To-GK in T. ovatus . Higher GK activity was found in fish fed 277.7 g kg − 1 carbohydrate diet. To-GK expression was higher in fish fed the 277.7 g kg − 1 carbohydrate diet. Overall, our data suggest that the hepatic GK activity and mRNA expression of T. ovatus were up-regulated significantly as dietary carbohydrate levels increased. These results indicated that To-GK plays a crucial role in the adaptation of hepatic glycolysis to dietary high carbohydrates in T. ovatus .