Dataset Information

Lymphocyte propionyl-CoA carboxylase is an early and sensitive indicator of biotin deficiency in rats, but urinary excretion of 3-hydroxypropionic acid is not.

ABSTRACT: Recent clinical studies have provided evidence that marginal biotin deficiency is more common than previously thought. The validity of that conclusion rests on two indicators of biotin status that depend on renal function. Our goal was to develop and assess the usefulness of two additional indicators in detecting marginal biotin status in a rat model, i.e., 1) activity of the biotin-dependent enzyme propionyl-CoA carboxylase in lymphocytes; and 2) urinary excretion of 3-hydroxypropionic acid, an organic acid that reflects decreased activity of propionyl-CoA carboxylase. Marginal-to-moderate biotin deficiency was induced experimentally by an egg-white diet (deficient rats); the biotin-supplemented rats were fed the egg-white diet plus supplemental biotin. Propionyl-CoA carboxylase activity was determined by an optimized H(14)CO(3)(-) incorporation assay. Urinary organic acids were determined by gas chromatography/mass spectrometry. Lymphocyte propionyl-CoA carboxylase activity decreased dramatically and in parallel with hepatic propionyl-CoA carboxylase activity. By d 7, lymphocyte propionyl-CoA carboxylase activity in each rat in the deficient group had decreased to less than the lowest value of any rat on d 0. By two-way ANOVA, the effects of diet (P < 0.0001), time (P < 0.005) and their interaction (P < 0.0001) were all significant. The urinary excretion of 3-hydroxypropionic acid did not differ between the two groups. Lymphocyte propionyl-CoA carboxylase activity is an early and sensitive indicator of marginal biotin deficiency, whereas the urinary excretion of 3-hydroxypropionic acid is not.

SUBMITTER: Mock DM

PROVIDER: S-EPMC1435358 | biostudies-literature | 2002 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Lymphocyte propionyl-CoA carboxylase is an early and sensitive indicator of biotin deficiency in rats, but urinary excretion of 3-hydroxypropionic acid is not.

Mock Donald M DM Mock Nell I NI

The Journal of nutrition 20020701 7

Recent clinical studies have provided evidence that marginal biotin deficiency is more common than previously thought. The validity of that conclusion rests on two indicators of biotin status that depend on renal function. Our goal was to develop and assess the usefulness of two additional indicators in detecting marginal biotin status in a rat model, i.e., 1) activity of the biotin-dependent enzyme propionyl-CoA carboxylase in lymphocytes; and 2) urinary excretion of 3-hydroxypropionic acid, an ...[more]

PMID: 12097674

Similar Datasets

Project description:The pathway of autotrophic CO2 fixation was studied in the phototrophic bacterium Chloroflexus aurantiacus and in the aerobic thermoacidophilic archaeon Metallosphaera sedula. In both organisms, none of the key enzymes of the reductive pentose phosphate cycle, the reductive citric acid cycle, and the reductive acetyl coenzyme A (acetyl-CoA) pathway were detectable. However, cells contained the biotin-dependent acetyl-CoA carboxylase and propionyl-CoA carboxylase as well as phosphoenolpyruvate carboxylase. The specific enzyme activities of the carboxylases were high enough to explain the autotrophic growth rate via the 3-hydroxypropionate cycle. Extracts catalyzed the CO2-, MgATP-, and NADPH-dependent conversion of acetyl-CoA to 3-hydroxypropionate via malonyl-CoA and the conversion of this intermediate to succinate via propionyl-CoA. The labelled intermediates were detected in vitro with either 14CO2 or [14C]acetyl-CoA as precursor. These reactions are part of the 3-hydroxypropionate cycle, the autotrophic pathway proposed for C. aurantiacus. The investigation was extended to the autotrophic archaea Sulfolobus metallicus and Acidianus infernus, which showed acetyl-CoA and propionyl-CoA carboxylase activities in extracts of autotrophically grown cells. Acetyl-CoA carboxylase activity is unexpected in archaea since they do not contain fatty acids in their membranes. These aerobic archaea, as well as C. aurantiacus, were screened for biotin-containing proteins by the avidin-peroxidase test. They contained large amounts of a small biotin-carrying protein, which is most likely part of the acetyl-CoA and propionyl-CoA carboxylases. Other archaea reported to use one of the other known autotrophic pathways lacked such small biotin-containing proteins. These findings suggest that the aerobic autotrophic archaea M. sedula, S. metallicus, and A. infernus use a yet-to-be-defined 3-hydroxypropionate cycle for their autotrophic growth. Acetyl-CoA carboxylase and propionyl-CoA carboxylase are proposed to be the main CO2 fixation enzymes, and phosphoenolpyruvate carboxylase may have an anaplerotic function. The results also provide further support for the occurrence of the 3-hydroxypropionate cycle in C. aurantiacus.

Project description:Propionic acidemia (PA) is a classical inborn error of metabolism with high morbidity that results from the inability of the propionyl-CoA carboxylase (PCC) enzyme to convert propionyl-CoA to methylmalonyl-CoA. PA is inherited in an autosomal recessive fashion due to functional loss of both alleles of either PCCA or PCCB. These genes are highly conserved across evolutionarily diverse species and share extensive similarity with pcca-1 and pccb-1 in the nematode, Caenorhabditis elegans. Here, we report the global metabolic effects of deletion in a single PCC gene, either pcca-1 or pccb-1, in C. elegans. Animal lifespan was significantly reduced relative to wild-type worms in both mutant strains, although to a greater degree in pcca-1. Mitochondrial oxidative phosphorylation (OXPHOS) capacity and efficiency as determined by direct polarography of isolated mitochondria were also significantly reduced in both mutant strains. While in vivo quantitation of mitochondrial physiology was normal in pccb-1 mutants, pcca-1 deletion mutants had significantly increased mitochondrial matrix oxidant burden as well as significantly decreased mitochondrial membrane potential and mitochondrial content. Whole worm steady-state free amino acid profiling by UPLC revealed reduced levels in both mutant strains of the glutathione precursor cysteine, possibly suggestive of increased oxidative stress. Intermediary metabolic flux analysis by GC/MS with 1,6-13C2-glucose further showed both PCC deletion strains had decreased accumulation of a distal tricarboxylic acid (TCA) cycle metabolic intermediate (+1 malate), isotopic enrichment in a proximal TCA cycle intermediate (+1 citrate), and increased +1 lactate accumulation. GC/MS analysis further revealed accumulation in the PCC mutants of a small amount of 3-hydroxypropionate, which appeared to be metabolized in C. elegans to oxalate through a unique metabolic pathway. Collectively, these detailed metabolic investigations in translational PA model animals with genetic-based PCC deficiency reveal their significantly dysregulated energy metabolism at multiple levels, including reduced mitochondrial OXPHOS capacity, increased oxidative stress, and inhibition of distal TCA cycle flux, culminating in reduced animal lifespan. These findings demonstrate that the pathophysiology of PA extends well beyond what has classically been understood as a single PCC enzyme deficiency with toxic precursor accumulation, and suggest that therapeutically targeting the globally disrupted energy metabolism may offer novel treatment opportunities for PA.SummaryTwo C. elegans model animals of propionic acidemia with single-gene pcca-1 or pccb-1 deletions have reduced lifespan with significantly reduced mitochondrial energy metabolism and increased oxidative stress, reflecting the disease's broader pathophysiology beyond a single enzyme deficiency with toxic precursor accumulation.

Dataset Information

Lymphocyte propionyl-CoA carboxylase is an early and sensitive indicator of biotin deficiency in rats, but urinary excretion of 3-hydroxypropionic acid is not.

Publications

Lymphocyte propionyl-CoA carboxylase is an early and sensitive indicator of biotin deficiency in rats, but urinary excretion of 3-hydroxypropionic acid is not.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets