Enoyl-CoA Hydratases in Bombina Orientalis Liver

Date of Graduation

Fall 2000


Master of Science in Chemistry


Chemistry and Biochemistry

Committee Chair

Dean Cuebas


It is well established that peroxisomal enoyl-CoA hydratases are involved in the ß-oxidative degradation of steroid side chain in the formation of bile acids in mammals, but there is no evidence regarding the role of hydratases in bile acid synthesis in amphibia. In this study, hydratase activities were investigated in the total, Bombina orientalis. Hydratase activity towards crotonyl-CoA was approximagely 25 times less in normal toads than in rats. Administration of di(2-ethylhexyl)phthalate (DEHP) and clofibrate to toads caused a 3- to 4-fold increase in the D-hydratase activity towards D-3-hydroxy-3-phenylpropionyl-CoA (D-3-OH-PPA-CoA), whereas no significant stimulation of the L-hydratase activites towards crotonyl-CoA, 2-decenoyl-CoA and L-3-OH-PPA-CoA was observed. In phosphocellulose chromatography, the peak of D-hydratase activity was significantly increased after treatment with peroxisome proliferators. No evidence was found in the proliferation of L-hydratase activity. Enoyl-CoA hydratase associated with dehydration of varanyl-CoA could not be detected in both the control and the treated toads. These data suggested that Bombina orientalis exhibits unique hydratase properties compared to the rat in the aspects of abundance, responses to clofibrate and DEHP, the elution profile in phosphocellulose chromatography, and the ability to dehydrate varanoyl-CoA.

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