Xylose Isomerase
Mostrando 1-12 de 68 artigos, teses e dissertações.
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1. Structural and biophysical studies of xylose isomerases for production of second generation ethanol / Estudos biofísicos e estruturais de xilose isomerases para produção de etanol de segunda geração
A demanda por combustíveis baseados em recursos renováveis é alta nos dias de hoje e tende a aumentar bastante no futuro. No Brasil, indústrias de biocombustíveis produzem principalmente etanol a partir cana-de-açúcar. A biomassa lignocelulósica, compreendendo resíduos de culturas, resíduos florestais, sólidos urbanos, é explorada como um elevado
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/08/2012
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2. Glucose(xylose) isomerase production by Streptomyces sp. CH7 grown on agricultural residues
Streptomyces sp. CH7 was found to efficiently produce glucose(xylose) isomerase when grown on either xylan or agricultural residues. This strain produced a glucose(xylose) isomerase activity of roughly 1.8 U/mg of protein when it was grown in medium containing 1% xylose as a carbon source. Maximal enzymatic activities of about 5 and 3 U/mg were obtained when
Braz. J. Microbiol.. Publicado em: 2012-09
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3. UDP-N-acetilglicosamina enolpiruvil transferase: determinação dos estados de protonação de resíduos de aminoácidos do sítio ativo pelo método PM6
UDP-N-acetylglucosamine-enolpyruvyl transferase (MurA) catalyzes the reaction between phosphoenol pyruvate and UDP-N-acetylglucosamine. We present a theoretical approach using the semiempirical PM6 method for defining protonation state of three active site residues, K22, H125, and K160. Prior comparison with neutron diffraction data showed that PM6 accuratel
Quím. Nova. Publicado em: 2012
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4. Xylose (glucose) isomerase gene from the thermophile Thermus thermophilus: cloning, sequencing, and comparison with other thermostable xylose isomerases.
The xylose isomerase gene from the thermophile Thermus thermophilus was cloned by using a fragment of the Streptomyces griseofuscus gene as a probe. The complete nucleotide sequence of the gene was determined. T. thermophilus is the most thermophilic organism from which a xylose isomerase gene has been cloned and characterized. The gene codes for a polypepti
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5. D-Glucose Isomerase: Constitutive and Catabolite Repression-Resistant Mutants of Streptomyces phaeochromogenes
As in other Streptomyces species, the enzymatic conversion of D-glucose to D-fructose is carried out in Streptomyces phaeochromogenes NRRL B-3559 by the inducible enzyme, D-xylose keto isomerase (EC 5.3.1.5.). Mutants of this microorganism were selected for their ability to grow on D-lyxose (2-epimer of D-xylose). As a result of the mutational event, the mic
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6. Sequence of the Ampullariella sp. strain 3876 gene coding for xylose isomerase.
The nucleotide sequence of the gene coding for xylose isomerase from Ampullariella sp. strain 3876, a gram-positive bacterium, has been determined. A clone of a fragment of strain 3876 DNA coding for a xylose isomerase activity was identified by its ability to complement a xylose isomerase-defective Escherichia coli strain. One such complementation positive
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7. Uptake and catabolism of D-xylose in Salmonella typhimurium LT2.
Salmonella typhimurium LT2 grows on D-xylose as sole carbon source with a generation time of 105 to 110 min. The following activities are induced at the indicated time after the addition of the inducer, D-xylose: D-xylulokinase (5 min), D-xylose isomerase (7 to 8 min), and D-xylose transport (10 min). All other pentoses and pentitols tested failed to induce
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8. xylA cloning and sequencing and biochemical characterization of xylose isomerase from Thermotoga neapolitana.
The xylA gene coding for xylose isomerase from the hyperthermophile Thermotoga neapolitana 5068 was cloned, sequenced, and expressed in Escherichia coli. The gene encoded a polypeptide of 444 residues with a calculated molecular weight of 50,892. The native enzyme was a homotetramer with a molecular weight of 200,000. This xylose isomerase was a member of th
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9. Ethanolic fermentation of xylose with Saccharomyces cerevisiae harboring the Thermus thermophilus xylA gene, which expresses an active xylose (glucose) isomerase.
The Thermus thermophilus xylA gene encoding xylose (glucose) isomerase was cloned and expressed in Saccharomyces cerevisiae under the control of the yeast PGK1 promoter. The recombinant xylose isomerase showed the highest activity at 85 degrees C with a specific activity of 1.0 U mg-1. A new functional metabolic pathway in S. cerevisiae with ethanol formatio
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10. Production and Purification of Extracellular D-Xylose Isomerase from an Alkaliphilic, Thermophilic Bacillus sp. †
An alkaliphilic, thermophilic Bacillus sp. (NCIM 59) produced extracellular xylose isomerase at pH 10 and 50°C by using xylose or wheat bran as the carbon source. The distribution of xylose isomerase as a function of growth in comparison with distributions of extra- and intracellular marker enzymes such as xylanase and β-galactosidase revealed that xylose
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11. Nucleotide sequence of the Bacillus subtilis xylose isomerase gene: extensive homology between the Bacillus and Escherichia coli enzyme.
The xylose isomerase gene from Bacillus subtilis was cloned from a genomic BamH1 library by complementation of an isomerase defective Escherichia coli strain as previously described. The ATG initiation codon is preceded by a Shine-Dalgarno sequence and two hexamers being characteristic for the promoter region of Bacillus genes. The structural gene consists o
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12. Selective cloning of Bacillus subtilis xylose isomerase and xylulokinase in Escherichia coli genes by IS5-mediated expression.
A fragment of Bacillus subtilis DNA coding for xylose isomerase and xylulokinase was isolated from a BamHI restriction pool by complementation of an isomerase-defective Escherichia coli strain. The spontaneous insertion of IS5, which occurred during the very slow growth of the E. coli xyl- cells on xylose, allowed the expression of the cloned Bacillus genes