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101.
Equilibrium constants for bromine hydrolysis, K(1) = [HOBr][H(+)][Br(-)]/[Br(2)(aq)], are determined as a function of ionic strength (&mgr;) at 25.0 degrees C and as a function of temperature at &mgr; approximately 0 M. At &mgr; approximately 0 M and 25.0 degrees C, K(1) = (3.5 +/- 0.1) x 10(-)(9) M(2) and DeltaH degrees = 62 +/- 1 kJ mol(-)(1). At &mgr; = 0.50 M and 25.0 degrees C, K(1) = (6.1 +/- 0.1) x 10(-)(9) M(2) and the rate constant (k(-)(1)) for the reverse reaction of HOBr + H(+) + Br(-) equals (1.6 +/- 0.2) x 10(10) M(-)(2) s(-)(1). This reaction is general-acid-assisted with a Br?nsted alpha value of 0.2. The corresponding Br(2)(aq) hydrolysis rate constant, k(1), equals 97 s(-)(1), and the reaction is general-base-assisted (beta = 0.8). 相似文献
102.
Thereza Christina Vessoni Penna Angela Faustino Jozala Thomas Rodolfo Gentille Adalberto Pessoa Jr. Olivia Cholewa 《Applied biochemistry and biotechnology》2006,129(1-3):334-346
Nisin, a bacteriocin produced during the exponential growth phase of Lactococcus lactis ATCC 11454, inhibits the growth of a broad range of Grampositive bacteria. Gram-negative bacteria can also be inhibited by nisin with EDTA. In this study, nisin production was assayed by the agar diffusion method using Lactobacillus sake ATCC 15521 and a recombinant Escherichia coli DH5-α expressing the recombinant green fluorescent protein as the nisin-susceptible test organisms. The titers of nisin expressed and released in culture media were quantified and expressed in arbitrary units (AU/mL of medium) and converted to standard nisin concentration (Nisaplin®, 25 mg of pure nisin with an activity of 1×106 AU/mL). The expression and release of nisin by L. lactis in skimmed milk (9.09% total solids) with Man Rugosa Shepeer-Bacto Lactobacilli broth (1∶1) was monitored in a 5 L New Brunswick fermentor. Combining EDTA with nisin increased the bactericidal effect of nisin on the bacteria examined. The presence of EDTA was necessary to inhibit E. coli growth with nisin. L. sake was shown to be a good indicator for the evaluation of nisin release in the culture media, including with the addition of EDTA. 相似文献
103.
Palligarnai T. Vasudevan Luting Olivia Li 《Applied biochemistry and biotechnology》1996,60(3):203-215
Studies of the kinetic behavior of horseradish peroxidase (HRP) at pH 8 and at room temperature indicate that the reaction
of phenol with H2O2 catalyzed by HRP exhibits normal Michaelis-Menten saturation kinetics. An irreversible reaction mechanism for the steady-state
kinetics of HRP, which is consistent with the experimental data, is considered. The second-order rate constants for the reactions
of HRP with H2O2 and compound II with phenol are 4.14 × 105 M-1s-1 and 5.54 × 104M-1s-1, respectively. 相似文献
104.
105.
106.
Hee-Sung Chae Olivia Dale Tahir Maqbool Mir Bharathi Avula Jianping Zhao Ikhlas A. Khan Shabana I. Khan 《Molecules (Basel, Switzerland)》2022,27(3)
Aquilaria sinensis (Lour.) Spreng is known for its resinous secretion (agarwood), often secreted in defense against injuries. We investigated the effects of A. sinensis flower extract (AF) on peroxisome proliferator-activated receptors alpha and gamma (PPARα and PPARγ), liver X receptor (LXR), glucose uptake, and lipid accumulation (adipogenesis). Activation of PPARα, PPARγ and LXR was determined in hepatic (HepG2) cells by reporter gene assays. Glucose uptake was determined in differentiated muscle (C2C12) cells using 2-NBDG (2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose). Adipogenesis was determined in adipocytes (3T3-L1 cells) by Oil red O staining. At a concentration of 50 µg/mL, AF caused 12.2-fold activation of PPARα and 5.7-fold activation of PPARγ, while the activation of LXR was only 1.7-fold. AF inhibited (28%) the adipogenic effect induced by rosiglitazone in adipocytes and increased glucose uptake (32.8%) in muscle cells at 50 μg/mL. It was concluded that AF acted as a PPARα/γ dual agonist without the undesired effect of adipogenesis and exhibited the property of enhancing glucose uptake. This is the first report to reveal the PPARα/γ dual agonistic action and glucose uptake enhancing property of AF along with its antiadipogenic effect, indicating its potential in ameliorating the symptoms of metabolic syndrome. 相似文献
107.
108.
Eduardo CortS Corts Elide HernNdez Cruz Olivia GarcÍA Mellado 《Journal of heterocyclic chemistry》1999,36(2):477-480
The preparation of eight novel substituted [1,2,4]oxadiazolo[4,5-a][1,5]benzodiazepines which have potentially useful pharmacological properties; by 1,3-cycloaddition of benzonitrile oxides, generated in situ from benzohydroxamoyl chloride and triethylamine, to 1,5-benzodiazepine derivatives is described. The structure of all products was corroborated by ir, 1H-nmr, 13C-nmr and ms. 相似文献
109.
Naroa Serna Olivia Cano-Garrido Laura Sánchez-García Mireia Pesarrodona Ugutz Unzueta Alejandro Sánchez-Chardi Ramon Mangues Esther Vázquez Antonio Villaverde 《Particle & Particle Systems Characterization》2020,37(6):2000040
Protein venoms are effective cytotoxic molecules that when conveniently targeted to tumoral markers can be exploited as promising anticancer drugs. Here, it is explored whether the structurally unrelated melittin, gomesin, and CLIP71 could be functionally active when engineered, in form of GFP fusions, as self-assembling multimeric nanoparticles. Incorporated in modular constructs including a C-terminal polyhistidine tag and an N-terminal peptidic ligand of the cytokine receptor CXCR4 (overexpressed in more than 20 human neoplasias), these venoms are well produced in recombinant bacteria as proteolytically stable regular nanoparticles ranging between 12 and 35 nm. Being highly fluorescent, these materials selectively penetrate, label, and kill CXCR4+ tumor cells in a CXCR4-dependent fashion. The obtained data support the concept of recombinant venoms as promising drugs, through the precise formulation as tumor-targeted nanomaterials for selective theragnostic applications in CXCR4+ cancers. 相似文献
110.
Sbastien Blanchard Loïc Le Clainche Marie-Noëlle Rager Benoît Chansou Jean-Pierre Tuchagues Arthur F. Duprat Yves Le Mest Olivia Reinaud 《Angewandte Chemie (International ed. in English)》1998,37(19):2732-2735
A cavity that acts as a molecular funnel is formed from calix[6]arene 1 and [CuI(NCCH3)4]PF6 [Eq. (a)]. An exchange of the well-protected acetonitrile ligand for other nitriles RCN is only possible with small R groups. The protection of the copper ions precludes oxidative dimerization; thus, the complexes mimic the mononuclear site of copper enzymes. 相似文献