Enzymatic Acylation
Mostrando 1-12 de 29 artigos, teses e dissertações.
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1. ENZYMATIC RESOLUTION OF ANTIDEPRESSANT DRUG PRECURSORS IN AN UNDERGRADUATE LABORATORY
The use of biocatalysts in synthetic chemistry is a conventional methodology for preparing enantiomerically enriched compounds. Despite this fact, the number of experiments in chemical teaching laboratories that demonstrate the potential of enzymes in synthetic organic chemistry is limited. We describe a laboratory experiment in which students synthesized a
Quím. Nova. Publicado em: 2015-02
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2. Síntese de ésteres derivados de carboidratos com propriedades surfactantes utilizando lipases imobilizadas em suporte sólido
Sugar esters constitute one of the main kinds of natural surfactants. These called biosurfactants show different advantages related to the synthetic surfactants. They are easily degraded in the ground and water with low toxicity what allows their industrial use in pharmaceutical food and cosmetic products. A particular strategy about these compounds is that
Publicado em: 2006
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3. Specific interaction between beta-lactams and soluble penicillin-binding protein 2a from methicillin-resistant Staphylococcus aureus: development of a chromogenic assay.
We investigated the enzymatic acylation of penicillin-binding protein 2a (PBP 2a) from methicillin-resistant Staphylococcus aureus by beta-lactams. Using a purified, soluble form of the protein (PBP 2a'), we observed beta-lactam-induced in vitro precipitation following first-order kinetics with respect to protein concentration. We used electrospray mass ioni
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4. Chemical synthesis of acyl thioesters of acyl carrier protein with native structure.
The acyl carrier protein (ACP) of Escherichia coli was converted to acyl-ACP by imidazole-catalyzed S-acylation with N-acylimidazole. The acylation was specific to the sulfhydryl group; no acylation of tyrosine or amino groups of the protein occurred. The acyl-ACP substrates synthesized had a native structure as determined by gel electrophoresis, hydrophobic
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5. Posttranslational processing of p21 ras proteins involves palmitylation of the C-terminal tetrapeptide containing cysteine-186.
The p21 proteins of ras oncogenes are synthesized as precursors in the cytosol. After processing, which involves acylation, the products are associated with the plasma membrane in eucaryotic cells. The p21 overproduced in Escherichia coli, however, is not processed by acylation. A synthetic tetrapeptide of the p21 C terminus is used to identify the acylation
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6. High-molecular-weight penicillin-binding proteins from membranes of bacilli.
Mixtures of high-molecular-weight, cephalosporin-sensitive penicillin-binding proteins (PBPs) can be purified from Bacillus subtilis membranes by cephalosporin affinity chromatography (G. Kleppe and J. L. Strominger, J. Biol. Chem. 254:4856-4862, 1979). By appropriate modification of this technique, B. subtilis PBP 1 was purified to homogeneity, and a mixtur
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7. Protein fatty acid acylation: enzymatic synthesis of an N-myristoylglycyl peptide.
Incubation of Saccharomyces cerevisiae strain JR153 with either [3H]myristate or [3H]palmitate demonstrates the synthesis of proteins that contain covalently bound fatty acids. A unique set of proteins is labeled by each fatty acid. Detailed analysis of a 20-kDa protein labeled with myristic acid demonstrates that myristate is linked to the amino-terminal gl
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8. Secondary Acylation of Vibrio cholerae Lipopolysaccharide Requires Phosphorylation of Kdo*
The lipopolysaccharide of Vibrio cholerae has been reported to contain a single 3-deoxy-d-manno-octulosonic acid (Kdo) residue that is phosphorylated. The phosphorylated Kdo sugar further links the hexa-acylated V. cholerae lipid A domain to the core oliogosaccharide and O-antigen. In this report, we confirm that V. cholerae possesses the enzymatic machinery
American Society for Biochemistry and Molecular Biology.
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9. Redundant Systems of Phosphatidic Acid Biosynthesis via Acylation of Glycerol-3-Phosphate or Dihydroxyacetone Phosphate in the Yeast Saccharomyces cerevisiae
In the yeast Saccharomyces cerevisiae lipid particles harbor two acyltransferases, Gat1p and Slc1p, which catalyze subsequent steps of acylation required for the formation of phosphatidic acid. Both enzymes are also components of the endoplasmic reticulum, but this compartment contains additional acyltransferase(s) involved in the biosynthesis of phosphatidi
American Society for Microbiology.
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10. Experimental evidence for kinetic proofreading in the aminoacylation of tRNA by synthetase.
The enzymatic aminoacylation of tRNA can be viewed as a means of proofreading either the amino acid or the tRNA or both. We have conducted further experimental tests of kinetic proofreading in discriminating between cognate and noncognate amino acids and tRNAs as follows: (formula: see text). In cases (i) and (ii) the amino acids are proofread, in cases (ii
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11. Do cleavages of amides by serine proteases occur through a stepwise pathway involving tetrahedral intermediates?
The mechanism of the serine protease-catalyzed cleavage of amides (acylation) was examined in terms of the basicity of the functional groups participating in the catalysis. It is proposed that the reaction does not proceed through a stepwise pathway, as opposed to the cleavage of esters and anilides, which start with general base-catalyzed formation of the t
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12. Biosynthesis of Rhizobium meliloti lipooligosaccharide Nod factors: NodA is required for an N-acyltransferase activity.
Rhizobium bacteria synthesize N-acylated beta-1,4-N-acetylglucosamine lipooligosaccharides, called Nod factors, which act as morphogenic signal molecules to legume roots during development of nitrogen-fixing nodules. The biosynthesis of Nod factors is genetically dependent upon the nodulation (nod) genes, including the common nod genes nodABC. We used the Rh