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Peer Reviewed Scientific Research Reports.
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1. Combined ultrasound-laccase assisted bleaching of cotton.
Match Strength: 4.255
This study evaluates the potential of using ultrasound to enhance the bleaching efficiency of laccase enzyme on cotton fabrics. Ultrasound of low intensity (7W) and relatively short reaction time (30 min) seems to act in a synergistic way with the enzyme in the oxidation/removal of the natural colouring matter of cotton. The increased bleaching effect could be attributed to improved diffusion of the enzyme from the liquid phase to the fibres surface and throughout the textile structure. On the other hand inactivation of the laccase occurred increasing the intensity of the ultrasound. However, ... Read More »
» Published in Ultrason Sonochem. 2007 Mar;14(3):350-4. Epub 2006 Sep 20.
2. Relationship between spermatozoon movement velocity and expression of testicular isoform of angiotensin-converting enzyme on their surface.
Match Strength: 4.240
The expression of testicular isoform of angiotensin-converting enzyme on the surface of human spermatozoa was evaluated by flow cytometry with monoclonal antibodies to epitopes of C-terminal domain of human angiotensin-converting enzyme and the mean path, mean curvilinear and straight-line velocities were determined by computer analysis of spermatozoon movement. A positive correlation between the expression of testicular isoform of angiotensin-converting enzyme on the cell surface and spermatozoon movement velocity was revealed. Publication Types: In Vitro, Research Support, Non-U.S. Gov ... Read More »
» Published in Bull Exp Biol Med. 2006 Feb;141(2):236-9.
3. Cell surface F1Fo ATP synthase: a new paradigm?
Match Strength: 3.863
The mitochondrial F1Fo adenosine triphosphate (ATP) synthase is one of the most thoroughly studied enzyme complexes known. Yet, a number of new observations suggesting that the enzyme is also located on the cell surface necessitate further investigation. While the mitochondrial synthase utilizes the proton gradient generated by oxidative phosphorylation to power ATP synthesis, the cell surface synthase has instead been implicated in numerous activities, including the mediation of intracellular pH, cellular response to antiangiogenic agents, and cholesterol homeostasis. Intriguingly, a common ... Read More »
» Published in Ann Med. 2006;38(6):429-38.
4. Gas phase noncovalent protein complexes that retain solution binding properties: Binding of xylobiose inhibitors to the beta-1, 4 exoglucanase from cellulomonas fimi.
Match Strength: 3.795
Tandem mass spectrometry has been used to compare gas-phase and solution binding of three small-molecule inhibitors to the wild type and three mutant forms of the catalytic domain of Cex, an enzyme that hydrolyses xylan and xylo-oligosaccharides. The inhibitors, xylobiosyl-deoxynojirimycin, xylobiosyl-isofagomine lactam, and xylobiosyl-isofagomine consist of a common distal xylose linked to different proximal aza-sugars. The three mutant forms of the enzyme contain the substitutions Asn44Ala, Gln87Met, and Gln87Tyr that alter the binding interactions between Cex and the distal sugar of each ... Read More »
» Published in J Am Soc Mass Spectrom. 2007 Jan;18(1):64-73. Epub 2006 Sep 26.
5. A novel SET domain methyltransferase in yeast: Rkm2-dependent trimethylation of ribosomal protein L12ab at lysine 10.
Match Strength: 3.779
The ribosomal protein L12ab (Rpl12ab) in Saccharomyces cerevisiae is modified by methylation at both arginine and lysine residues. Although the enzyme responsible for the modification reaction at arginine 66 has been identified (Rmt2), the enzyme(s) responsible for the lysine modification(s) has not been found, and the site(s) of methylation has not been determined. Here we demonstrate, using a combination of mass spectrometry and labeling assays, that the yeast gene YDR198c encodes the enzyme responsible for the predominant epsilon-trimethylation at lysine 10 in Rpl12ab. An additional site of ... Read More »
» Published in J Biol Chem. 2006 Nov 24;281(47):35835-45. Epub 2006 Sep 27.
6. Peroxiredoxin 6 is a potent cytoprotective enzyme in the epidermis.
Match Strength: 3.749
Peroxiredoxin 6 is an enzyme that detoxifies hydrogen peroxide and various organic peroxides. In previous studies we found strongly increased expression of peroxiredoxin 6 in the hyperproliferative epidermis of wounded and psoriatic skin, suggesting a role of this enzyme in epidermal homeostasis. To address this question, we generated transgenic mice overexpressing peroxiredoxin 6 in the epidermis. Cultured keratinocytes from transgenic mice showed enhanced resistance to the toxicity of various agents that induce oxidative stress. However, overexpression of peroxiredoxin 6 did not affect skin ... Read More »
» Published in Am J Pathol. 2006 Oct;169(4):1194-205.
7. Expression, purification, and characterization of stable, recombinant human adenylosuccinate lyase.
Match Strength: 3.664
The full length human adenylosuccinate lyase gene was generated by a PCR method using a plasmid encoding a truncated human enzyme as template, and was cloned into a pET-14b vector. Human adenylosuccinate lyase was overexpressed in Escherichia coli Rosetta 2(DE3)pLysS as an N-terminal histidine-tagged protein and was purified to homogeneity by a nickel-nitriloacetic acid column at room temperature. The histidine tag was removed from the human enzyme by thrombin digestion and the adenylosuccinate lyase was purified by Sephadex G-100 gel filtration. The histidine-tagged and non-tagged ... Read More »
» Published in Protein Expr Purif. 2007 Feb;51(2):227-34. Epub 2006 Aug 9.
8. Optically trapping confocal Raman microscopy of individual lipid vesicles: kinetics of phospholipase A(2)-catalyzed hydrolysis of phospholipids in the membrane bilayer.
Match Strength: 3.662
Phospholipase A(2) (PLA(2))-catalyzed hydrolysis at the sn-2 position of 1,2-dimyristoyl-sn-glycero-3-phosphocholine in optically trapped liposomes is monitored in situ using confocal Raman microscopy. Individual optically trapped liposomes (0.6 microm in diameter) are exposed to PLA(2) isolated from cobra (Naja naja naja) venom at varying enzyme concentrations. The relative Raman scattering intensities of C-C stretching vibrations from the trans and gauche conformers of the acyl chains are correlated directly with the extent of hydrolysis, allowing the progress of the reaction to be monitored ... Read More »
» Published in Anal Chem. 2006 Oct 1;78(19):6928-35.
9. A quick release mechanism for abscisic acid.
Match Strength: 3.661
The hormone abscisic acid regulates development and survival of plants in response to environmental stresses. now demonstrate that in response to stress, abscisic acid can be made available via polymerization of a beta-glucosidase enzyme. This enzyme is reported to hydrolyze glucose-conjugated abscisic acid, thus increasing active abscisic acid concentrations. Publication Types: Comment, ... Read More »
» Published in Cell. 2006 Sep 22;126(6):1023-5. Comment on: Cell. 2006 Sep 22;126(6):1109-20.
10. N-phosphonacetyl-L-isoasparagine a potent and specific inhibitor of Escherichia coli aspartate transcarbamoylase.
Match Strength: 3.513
The synthesis of a new inhibitor, N-phosphonacetyl-L-isoasparagine (PALI), of Escherichia coli aspartate transcarbamoylase (ATCase) is reported, as well as structural studies of the enzyme.PALI complex. PALI was synthesized in 7 steps from beta-benzyl L-aspartate. The KD of PALI was 2 microM. Kinetics and small-angle X-ray scattering experiments showed that PALI can induce the cooperative transition of ATCase from the T to the R state. The X-ray structure of the enzyme.PALI complex showed 22 hydrogen-bonding interactions between the enzyme and PALI. The kinetic characterization and crystal ... Read More »
» Published in J Med Chem. 2006 Oct 5;49(20):5932-8.
11. Positively charged C-terminal subdomains of EcoRV endonuclease: contributions to DNA binding, bending, and cleavage.
Match Strength: 3.493
The carboxy-terminal subdomains of the homodimeric EcoRV restriction endonuclease each bear a net charge of +4 and are positioned on the inner concave surface of the 50 degree DNA bend that is induced by the enzyme. A complete kinetic and structural analysis of a truncated EcoRV mutant lacking these domains was performed to assess the importance of this diffuse charge in facilitating DNA binding, bending, and cleavage. At the level of formation of an enzyme-DNA complex, the association rate for the dimeric mutant enzyme was sharply decreased by 10(3)-fold, while the equilibrium dissociation ... Read More »
» Published in Biochemistry. 2006 Sep 26;45(38):11453-63.
12. The immunoglobulin A1 proteinase from Streptococcus pneumoniae is inhibited by tetracycline compounds.
Match Strength: 3.401
Streptococcus pneumoniae produces a zinc-dependent proteinase that cleaves human immunoglobulin (Ig) A1 in the hinge region. This metalloproteinase is hypothesized to act as a virulence factor by allowing S. pneumoniae to evade the protection provided by IgA1, thus enhancing its ability to colonize the human nasopharyngeal region. No biologically compatible inhibitors of this enzyme have been identified. We determined that doxycycline and a chemically modified tetracycline inhibit this enzyme in vitro at low micromolar concentrations ... Read More »
» Published in FEMS Immunol Med Microbiol. 2006 Nov;48(2):218-22. Epub 2006 Sep 21.
13. Replacement surgery with unnatural amino acids in the lock-and-key joint of glutathione transferase subunits.
Match Strength: 3.391
Proteins contain amino acid residues essential to structure and function. Ribosomal protein synthesis is typically limited to the 20 amino acids of the genetic code, but posttranslational chemical modifications can greatly expand the diversity of side chain functionalities. In this investigation, a natural aromatic residue in the lock-and-key joint at the subunit interface of the dimeric glutathione transferase P1-1 was replaced by an S-alkylcysteine residue to give a functional enzyme. Introduction of Cys in the key position inactivates the enzyme, but subsequent alkylation of this residue ... Read More »
» Published in Chem Biol. 2006 Sep;13(9):929-36.
14. Increased prevalence of dihydropyrimidine dehydrogenase deficiency in African-Americans compared with Caucasians.
Match Strength: 3.357
PURPOSE: African-American patients with colorectal cancer were observed to have increased 5-fluorouracil (5-FU)-associated toxicity (leukopenia and anemia) and decreased overall survival compared with Caucasian patients. One potential source for this disparity may be differences in 5-FU metabolism. Dihydropyrimidine dehydrogenase (DPD), the initial and rate-limiting enzyme of 5-FU catabolism, has previously been shown to have significant interpatient variability in activity. Several studies have linked reduced DPD activity to the development of 5-FU toxicity. Although the distribution of DPD ... Read More »
» Published in Clin Cancer Res. 2006 Sep 15;12(18):5491-5.
15. Acid stability of carbon paste enzyme electrodes.
Match Strength: 3.334
This note reports on the unusual protection of several enzymes against harsh pH conditions provided by carbon paste electrodes. Both glucose oxidase and polyphenol oxidase carbon paste amperometric biosensors display a remarkable resistance to acid deactivation compared to conventional biosensors prepared by electropolymeric entrapment of enzymes. For example, the carbon paste enzyme electrodes fully retain their activity upon stressing in strongly acidic conditions (pH approximately 2.0-2.5) for prolonged periods, where conventional (polymer-based) biosensors rapidly lose most of their ... Read More »
» Published in Anal Chem. 2006 Oct 1;78(19):7044-7.
16. Experimental evidence for allosteric modifier saturation as predicted by the bi-substrate Hill equation.
Match Strength: 3.271
The cooperative enzyme reaction rates predicted by the bi-substrate Hill equation and the bi-substrate Monod-Wyman-Changeux (MWC) equation when allosterically inhibited are compared in silico. Theoretically, the Hill equation predicts that when the maximum inhibitory effect at a certain substrate condition has been reached, an increase in allosteric inhibitor concentration will have no effect on reaction rate, that is the Hill equation shows allosteric inhibitor saturation. This saturating inhibitory effect is not present in the MWC equation. Experimental in vitro data for pyruvate kinase, a ... Read More »
» Published in Syst Biol (Stevenage). 2006 Sep;153(5):342-5.
17. Endothelin-converting enzyme expression in the neointima after percutaneous coronary intervention.
Match Strength: 3.223
Smooth muscle cells (SMCs) are the major cellular component of neointimal tissues after percutaneous coronary intervension (PCI). Endothelin-1 (ET-1) is a powerful vasoconstrictor and has a mitogenic effect on SMCs. Endothelin-converting enzyme (ECE) is a key enzyme in the process of ET-1 generation. However, the expression of ECE in association with post-PCI repair processes has not been reported. Thirteen coronary sites after PCI obtained at autopsy and 6 atherectomy specimens obtained from restenotic sites were investigated. Frozen sections were stained with antibodies against ECE, SMCs, ... Read More »
» Published in Osaka City Med J. 2006 Jun;52(1):29-37.
18. The inhibition of mitochondrial complex I (NADH:ubiquinone oxidoreductase) by Zn2+.
Match Strength: 3.211
NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria is a highly complicated, membrane-bound enzyme. It is central to energy transduction, an important source of cellular reactive oxygen species, and its dysfunction is implicated in neurodegenerative and muscular diseases and in aging. Here, we describe the effects of Zn2+ on complex I to define whether complex I may contribute to mediating the pathological effects of zinc in states such as ischemia and to determine how Zn2+ can be used to probe the mechanism of complex I. Zn2+ inhibits complex I more strongly than Mg2+, ... Read More »
» Published in J Biol Chem. 2006 Nov 17;281(46):34803-9. Epub 2006 Sep 15.
19. Improved metabolic stimulus for glucose-induced insulin secretion through GK and PFK-2/FBPase-2 coexpression in insulin-producing RINm5F cells.
Match Strength: 3.194
The glucose sensor enzyme glucokinase plays a pivotal role in the regulation of glucose-induced insulin secretion in pancreatic beta-cells. Activation of glucokinase represents a promising concept for the treatment of type 2 diabetes. Therefore, we analyzed the glucokinase activation through its physiological interaction partner, the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) and the resulting effect on glucose metabolism in insulin-producing cells. In RINm5F-GK-PFK-2/FBPase-2 cells stably overexpressing glucokinase plus islet PFK-2/FBPase-2, ... Read More »
» Published in Endocrinology. 2006 Dec;147(12):5768-76. Epub 2006 Sep 15.
20. Pig liver phosphomevalonate kinase: kinetic mechanism.
Match Strength: 3.184
Phosphomevalonate kinase catalyzes the phosphorylation of phosphomevalonate to diphosphomevalonate by ATP, one of the initial steps in the biosynthesis of steroids and isoprenoids. In previous studies, the enzyme from pig liver was purified and characterized, and preliminary work showed that the enzyme follows hyperbolic kinetics and a sequential mechanism. The present work is a more detailed analysis of its kinetic mechanism, using initial velocity and isotope exchange at equilibrium measurements. The results are compatible with a Bi Bi sequential ordered mechanism with phosphomevalonate as ... Read More »
» Published in Arch Biochem Biophys. 2006 Oct 15;454(2):189-96. Epub 2006 Aug 22.
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