RESUMO
Knowledge of genetic polymorphisms of metabolizing enzymes of medical drugs and xenobiotics including cytochrome P450 (CYP) is very limited in cats. We investigated polymorphisms in CYP1A2, one of the major CYP isoforms in the feline liver. Wild-type and three non-synonymous polymorphic variants, but no synonymous variant, were identified in feline CYP1A2 in 50 alleles of domestic cats in Japan. Metabolic parameters, Km and Vmax, of ethoxyresorufin hydroxylation by CYP1A2 were shown to range within two times for identified non-synonymous variants by using a heterologous coexpression system. The results confirmed the polymorphic nature of CYP1A2 as a basis for effective application of medicines and prevention of adverse reactions in the treatment of domestic cats as well as for hereditary disorders.
Assuntos
Gatos/genética , Gatos/metabolismo , Citocromo P-450 CYP1A2/genética , Variação Genética , Animais , Cumarínicos/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Feminino , Hidroxilação , Fígado/enzimologia , Masculino , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNARESUMO
Knowledge of genetic polymorphisms of cytochrome P450 (CYP), the most important xenobiotic metabolizing enzyme, is very limited in cats. Preliminarily, we investigated genetic polymorphisms in CYP2A13, one of the major CYP isoforms in the liver and lung. Four synonymous and three non-synonymous polymorphic variants were identified in feline CYP2A13 in domestic cats in Japan, without an obvious major type. Metabolic parameters, Km and Vmax, of coumarin hydroxylation of CYP2A13 were shown to range within two times for the identified non-synonymous polymorphic variants by using heterologous coexpression system in Escherichia coli. The results confirmed the polymorphic nature of CYP2A13 as a basis for effective application of medicines and prevention of adverse reactions in treatment of domestic cats.
Assuntos
Hidrocarboneto de Aril Hidroxilases/genética , Hidrocarboneto de Aril Hidroxilases/metabolismo , Gatos/genética , Variação Genética , Esteroide Hidroxilases/genética , Esteroide Hidroxilases/metabolismo , Animais , Gatos/metabolismo , Cumarínicos/metabolismo , Feminino , Hidroxilação , Fígado/enzimologia , Masculino , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNARESUMO
Knowledge on genetic polymorphisms of metabolising enzymes including cytochrome P450 (CYP) is very limited in cats. We investigated polymorphisms in CYP3A131, one of the major CYP isoforms in the feline liver and small intestine. Eight non-synonymous variants and one synonymous variant of feline CYP3A131 were identified in 29 cats. A major non-synonymous type was not observed. Metabolic parameters (Km and Vmax) of dibenzylfluorescein hydroxylation were ranged within about 2 times for the identified non-synonymous variants by using a heterologous coexpression system of CYP3A131 and feline cytochrome P450 reductase in Escherichia coli. The results confirmed the polymorphic nature of CYP3A131 as a basis for effective application of medicines and prevention of adverse reactions in the treatment of domestic cats.
Assuntos
Gatos/genética , Gatos/metabolismo , Citocromo P-450 CYP3A/genética , Variação Genética , Animais , Citocromo P-450 CYP3A/metabolismo , Escherichia coli , Feminino , Hidroxilação , Intestino Delgado/enzimologia , Fígado/enzimologia , Masculino , NADPH-Ferri-Hemoproteína RedutaseRESUMO
1. Compared to information for herbivores and omnivores, knowledge on xenobiotic metabolism in carnivores is limited. The cytochrome P450 2C (CYP2C) subfamily is recognized as one of the most important CYP groups in human and dog. We identified and characterized CYP2C isoforms and variants in cat, which is an obligate carnivore. 2. Quantitative RT-PCR and immunoblot analyses were carried out to evaluate the expression of CYP2C in the liver and small intestine. A functional CYP2C isoform was heterologously expressed in yeast microsomes to determine the enzymatic activity. 3. Cat had two CYP2C genes, 21 and 41, in the genome; however, CYP2C21P was a pseudogene that had many stop codons. Three splicing variants of CYP2C41 were identified (v1-v3), but only one of them (v1) showed a complete deduced amino acid sequence as CYP2C protein. Transcripts of feline CYP2C41v1 were detected but the amounts were negligible or very small in the liver and small intestine. Immunoreactivity to an antihuman CYP2C antibody was confirmed in the recombinant feline CYP2C41v1 but not in the feline liver. 4. Recombinant feline CYP2C41v1 metabolized several substrates, including dibenzylfluorescein that is specific to human CYP2C. 5. The results suggest a limited role of functional CYP2C isoforms in xenobiotic metabolism in cat.
