Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.5.5 (CPS)
 1,262 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The early enzymes of arginine biosynthesis in Neurospora crassa are localized in the mitochondrion and catalyze the conversion of glutamate to citrulline. The final conversion of citrulline to arginine occurs via two enzymatic steps in the cytoplasm. We have devised a method for the isolation and purification of three of the mitochondrial arginine biosynthetic enzymes from a single extract. Acetylglutamate kinase and acetylglutamyl-phosphate reductase (both products of the complex arg-6 locus) were purified to homogeneity and near homogeneity, respectively. The large catalytic subunit of carbamoyl-phosphate synthetase was also purified to homogeneity. The three enzymes were resolved into separate fractions by chromatography on three dye-ligand affinity resins, which are specific for nucleotide binding enzymes and have a high protein binding capacity. High performance liquid chromatography was employed in the final stages of purification and was extremely effective in fractionating both acetylglutamate kinase and acetylglutamyl-phosphate reductase from proteins with very similar properties, which were not removed by other techniques. The purified proteins were used to raise specific antisera against these proteins. Acetylglutamate kinase and acetylglutamyl-phosphate reductase were shown to be immunologically unrelated. This finding suggests that the arg-6 locus encompasses two nonoverlapping cistrons. The antisera raised against carbamoyl-phosphate synthetase has been shown to cross-react with related enzymes in Saccharomyces cerevisiae, Escherichia coli, and rat liver (Ness, S. A., and Weiss, R. L. (1985) J. Biol. Chem. 260, 14355-14362). Acetylglutamate kinase is a regulatory enzyme and has been shown to be feedback-inhibited by arginine. We have determined the submitochondrial localization of acetylglutamate kinase and the second arg-6 product, acetylglutamyl-phosphate reductase. Both enzymes were shown to be soluble matrix enzymes. We discuss the relevance of this finding with respect to possible mechanisms for end product inhibition of a mitochondrial enzyme by a cytoplasmic effector.
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PMID:Simultaneous purification of three mitochondrial enzymes. Acetylglutamate kinase, acetylglutamyl-phosphate reductase and carbamoyl-phosphate synthetase from Neurospora crassa. 242 Jul 93

Agrobacterium tumefaciens-mediated transformation (ATMT) was used for random insertional mutagenesis to identify pathogenicity genes in the hemibiotrophic fungus Colletotrichum higginsianum. A high-throughput primary infection assay on Arabidopsis thaliana seedlings allowed the rapid screening of 8,850 transformants. Forty mutants showing reproducible pathogenicity defects on Arabidopsis and Brassica plants were obtained, and their infection phenotypes were characterized microscopically. Six mutants were impaired in appressorial melanization, fifteen had reduced penetration ability, 14 induced host papillae or hypersensitive cell death, and five were affected in the transition from biotrophy to necrotrophy. Southern blot analysis showed 58% of the transformants had single-site T-DNA integrations. Right-border flanking sequences were recovered from 12 mutants by inverse polymerase chain reaction (PCR) or thermal asymmetric interlaced PCR and were used to isolate the tagged genes from a genomic library. The putative pathogenicity genes encoded homologs of a major facilitator superfamily phosphate transporter, importin-beta2, ornithine decarboxylase, beta-1,3(4)-glucanase, ATP-binding endoribonuclease, carbamoyl-phosphate synthetase, and the polyprotein precursor of N-acetylglutamate kinase and N-acetylglutamyl-phosphate reductase. Six further loci were homologous to proteins of unknown function. None of these genes were previously implicated in the pathogenicity of any Colletotrichum species. The results demonstrate that ATMT is an effective tool for gene discovery in this model pathogen.
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PMID:Discovery of pathogenicity genes in the crucifer anthracnose fungus Colletotrichum higginsianum, using random insertional mutagenesis. 1913 67

African Americans are disproportionately affected by asthma. Social and economic factors play a role in this disparity, but there is evidence that genetic factors may also influence the development of asthma and response to therapy in African American children. Our hypothesis is that variations in asthma related genes contribute to the observed asthma disparities by influencing the response to asthma-specific therapy. In order to test this hypothesis, we characterized the clinical response to asthma-specific therapy in 107 African American children who presented to the emergency room in status asthmaticus, with a primary outcome indicator of length of time on continuous albuterol. Single locus analysis indicated that genotype variation in glutathione-dependent S-nitrosoglutathione reductase (GSNOR) is associated with a decreased response to asthma treatment in African American children. A post hoc multi-locus analysis revealed that a combination of four single nucleotide polymorphisms (SNPs) within GSNOR, adrenergic receptor beta 2, and carbamoyl phosphate synthetase-1 give a 70% predictive value for lack of response to therapy. This predictive model needs replication in other cohorts of patients with asthma, but suggests gene-gene interactions may have greater significance than that identified with single variants. Our findings also suggest that genetic variants may contribute to the observed population disparities in asthma.
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PMID:Genetic variants of GSNOR and ADRB2 influence response to albuterol in African-American children with severe asthma. 1951 54