Your browser doesn't support javascript.
loading
Differential effects of biotin deficiency and replenishment on rat liver pyruvate and propionyl-CoA carboxylases and on their mRNAs.
Rodríguez-Meléndez, R; Pérez-Andrade, M E; Díaz, A; Deolarte, A; Camacho-Arroyo, I; Cicerón, I; Ibarra, I; Velázquez, A.
Afiliação
  • Rodríguez-Meléndez R; Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas UNAM and Instituto Nacional de Pediatría, Mexico City, Mexico.
Mol Genet Metab ; 66(1): 16-23, 1999 Jan.
Article em En | MEDLINE | ID: mdl-9973543
Although the role of vitamins as prosthetic groups of enzymes is well known, their participation in the regulation of their genetic expression has been much less explored. We studied the effect of biotin on the genetic expression of rat liver mitochondrial carboxylases: pyruvate carboxylase (PC), propionyl-CoA carboxylase (PCC), and 3-methylcrotonyl-CoA carboxylase (MCC). Rats were made biotin-deficient and were sacrificed after 8 to 10 weeks, when deficiency manifestations began to appear. At this time, hepatic PCC activity was 20% of the control values or lower, and there was an abnormally high urinary excretion of 3-hydroxyisovaleric acid, a marker of biotin deficiency. Biotin was added to deficient primary cultured hepatocytes. It took at least 24 h after the addition of biotin for PCC to achieve control activity and biotinylation levels, whereas PC became active and fully biotinylated in the first hour. The enzyme's mass was assessed in liver homogenates from biotin-deficient rats and incubated with biotin to convert the apocarboxylases into holocarboylases, which were detected by streptavidin blots. The amount of PC was minimally affected by biotin deficiency, whereas that of the alpha subunits of PCC and of MCC decreased substantially in deficient livers, which likely explains the reactivation and rebiotinylation results. The expression of PC and alphaPCC was studied at the mRNA level by Northern blots and RT/PCR; no significant changes were observed in the deficient livers. These results suggest that biotin regulates the expression of the catabolic carboxylases (PCC and MCC), that this regulation occurs after the posttranscriptional level, and that pyruvate carboxylase, a key enzyme for gluconeogenesis, Krebs cycle anaplerosis, and fatty acid synthesis, is spared of this control.
Assuntos
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Piruvato Carboxilase / Biotina / RNA Mensageiro / Carboxiliases / Fígado Limite: Animals Idioma: En Revista: Mol Genet Metab Assunto da revista: BIOLOGIA MOLECULAR / BIOQUIMICA / METABOLISMO Ano de publicação: 1999 Tipo de documento: Article País de afiliação: México País de publicação: Estados Unidos
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Piruvato Carboxilase / Biotina / RNA Mensageiro / Carboxiliases / Fígado Limite: Animals Idioma: En Revista: Mol Genet Metab Assunto da revista: BIOLOGIA MOLECULAR / BIOQUIMICA / METABOLISMO Ano de publicação: 1999 Tipo de documento: Article País de afiliação: México País de publicação: Estados Unidos