Citrate isolation

Feng TL, Gurian PL, Healy MD, Barron AR (1990) Aluminum citrate isolation and stractural characterization of a stable trinuclear complex. Inorg Chem 29 408-411 Fitzgerald JJ, Rosenberg AH (1999) Chemistry of aluminum chlorohydrate and activated aluminum chlorohydrate. In Antiperspirants and Deodorants, 2nd edition. Laden K (ed) Marcel Dekker, New York, p 83-136... 

Eeng, T. L., Gurian, P. L.. Healy, M. D.. and Barron, A. R. (1990). Aluminum citrate isolation and structural characterization of a stable trinuclear complex. Inorg. Chem. 29, 408-411. 

OC-Hydroxycarboxylic Acid Complexes. Water-soluble titanium lactate complexes can be prepared by reactions of an aqueous solution of a titanium salt, such as TiCl, titanyl sulfate, or titanyl nitrate, with calcium, strontium, or barium lactate. The insoluble metal sulfate is filtered off and the filtrate neutralized using an alkaline metal hydroxide or carbonate, ammonium hydroxide, amine, or alkanolamine (78,79). Similar solutions of titanium lactate, malate, tartrate, and citrate can be produced by hydrolyzation of titanium salts, such as TiCl, in strongly (>pH 10) alkaline water isolation of the... 

The opportunity of use of a ternary complex of ions Eu(III) with oxatetracycline (OxTC) and citrat-ions (Cit) for luminescent detection of OxTC in milk after chromatographic isolation is shown. 

Extraction and purification of luciferin and luciferase (Viviani etal., 2002a) To isolate luciferin, the lanterns of the Australian A. flava were homogenized in hot 0.1 M citrate buffer, pH 5, and the mixture was heated to 95°C for 5 min. The mixture was acidified to pH 2.5-3.0 with HCl, and luciferin was extracted with ethyl acetate. Upon thin-layer chromatography (ethanol-ethyl acetate-water, 5 3 2 or 3 5 2), the active fraction of luciferin was fluorescent in purple (emission Lav 415 nm when excited at 290 nm). To isolate the luciferase, the cold-water extract prepared according to Wood (1993 see above) was chromatographed on a column of Sephacryl S-300. On the same... 

Bacteria have been isolated using reduced anthraquinone-2,6-disulfonate (HjAQDS) as electron donor and nitrate as electron acceptor (Coates et al. 2002). The organisms belonged to the a-, p-, y-, and 5-subdivision of the Proteobacteria, and were able to couple the oxidation of H AQDS to the reduction of nitrate with acetate as the carbon source. In addition, a number of C2 and C3 substrates could be used including propionate, butyrate, fumarate, lactate, citrate, and pyruvate. 

Cultivation of strictly anaerobic organisms requires not only that the medium be oxygen-free, but also that the redox potential of the medium be compatible with that required by the organisms. This may be accomplished by addition of reducing agents such as sulfide, dithionite, titanium(III) citrate, or titanium(IIl) nitrilotriacetate. Any of these may, however, be toxic so that only low concentrations should be employed. Attention has been drawn to the fact that titanium(III) citrate-reduced medium may be inhibitory to bacteria during initial isolation (Wachenheim and Hespell 1984). 

In vitro platelet activation is dependent on the anticoagulant that is used for blood collection. In one study it was demonstrated that PF4 levels in platelet-poor plasma isolated after incubation without any stimuli for 1 hour at 37°C were as follows conventional heparin, 1180 ng/ml hirudin, 469 ng/ml citrate, 440 ng/ml and EDTA, 217 ng/ml (110). EDTA appears to suppress platelet degranulation. PF4 levels obtained with a low-molecular-weight heparin preparation called Frag-min were, however, comparable to those obtained with hirudin (110). 

Biochemical tests are usually performed after pure cultures have been obtained. The standard indole, methyl red, Voges-Proskauer, citrate, and litmus milk tests may be used to show important physiological characteristics. To study the functional diversity of bacteria, the utilization of carbohydrates, amines, amides, carboxylic acids, amino acids, polymers, and other carbon and nitrogen sources can be tested.28 Dilution-based most-probable number (MPN) techniques with phospholipid fatty acids as biomarkers have been employed for studying different bacterial species in lakes.40 The patterns of antibiotic resistance in bacteria isolated from natural waters have been useful for identifying sources of water pollution.34... 

Widespread medicinal use of colloidal bismuth subcitrate (CBS) has prompted extensive studies of bismuth compounds involving the citrate anion. Bismuth citrate is essentially insoluble in water, but a dramatic increase in solubility with increasing pH has been exploited as a bio-ready source of soluble bismuth, a material referred to as CBS. Formulation of these solutions is complicated by the variability of the bismuth anion stoichiometry, the presence of potassium and/ or ammonium cations, the susceptibility of bismuth to oxygenation to Bi=0, and the incorporation of water in isolated solids. Consequently, a variety of formulas are classified in the literature as CBS. Solids isolated from various, often ill-defined combinations of bismuth citrate, citric acid, potassium hydroxide, or ammonium hydroxide have been assigned formulas on the basis of elemental analysis data or by determination of water and ammonia content, but are of low significance in the absence of complementary data other than thermal analysis (163), infrared spectroscopy (163), or NMR spectroscopy (164). In this context, the Merck index lists the chemical formula of CBS as KgfNHJaBieOafOHMCeHsCbh in the 11th edition (165), but in the most recent edition provides a less precise name, tripotassium dicitrato bismuthate (166). 

Aconitase, an unstable enzyme,4 is concerned with the reversible conversion of cis-aconitate to either citric acid or isocitric acid. It may be noted that the entire system of tricarboxylic cycle enzymes are present in the mitochondria separated from cells, and, furthermore, it has been found that the mitochondrial enzymes differ from the isolated enzymes in that the former require no addition of D.P.N. (co-enzyme I) or T.P.N. (co-enzyme II) for activity. Peters suggests that the citrate accumulation is caused by the competitive reaction of the fluorocitrate with aconitase required for the conversion of citrate to isocitrate. This interference with the tricarboxylic acid... 

The key to unraveling the toxicity of fluoracetate came from observations of Buffa and Peters (1949) that in animals treated with FAc, considerable quantities of citrate accumulated in some tissues. Oxygen uptake was also diminished. The citric acid cycle was thus implicated as the site of inhibition. Fluorcitrate was then isolated from the affected tissues. It was found to be a powerful competitive inhibitor of aconitase, thus blocking citrate oxidation. The suggestion was therefore made that fluoracetate was toxic not in itself, but because it was metabolized in cells via fluoracetyl CoA to give a toxic derivative, an example of lethal synthesis —the capacity of organisms to metabolize nontoxic compounds and convert them to potentially lethal products. 

If 15N ammonium citrate was administered, and glutamate, aspartate, and glycine isolated from liver and intestinal wall protein, all showed 15N uptake. From the results of labeling studies, Schoenheimer finished his Edward K.Dunham lectures in Harvard in 1941 with the phrase— the structural materials [of the body] are in a steady state of flux. The classical picture must thus be replaced by one which takes account of the dynamic state of body structure —an idea which has become an integral part of biochemistry since that time, and which was almost totally dependent on the introduction of isotopes for its discovery. 

Human neutrophils are isolated from acid citrate dextrose solution-A anticoagulated human blood by the method described by Boyum (16) with modifications (17) as described in detail in Chapter 36 of this text. 

In addition to the circumstantial iji vivo evidence for fluorocitrate as the ultimate biochemical lesion we desired to demonstrate unambiguously that it was produced as a metabolite of 29-fluorostigmasterol. The toxicity of fluorocitrate and the resulting lethal accumulation of citrate in mouse, fly and cockroach tissues have been shown in early experiments with fluoroacetamide and fluoroacetate(24). However, to our knowledge, complete characterization of (2R,3R)-2-fluorocitrate as the lethal metabolite in vivo has not previously been reported. We thus prepared( ) [29- ]-29-fluorostigmasterol, [29- H]-29-Huorositosterol and [16- H]-16-fluorohexadec-9-enoic acid to enable isolation of [2-3H]-2-fluorocitrate from vivo incubations using Manduca sexta. 

Potent metabolic inhibitors of the citric acid cycle. Fluo-roacetate (F-CH2COO ) must first be converted to flu-oroacetyl-S-CoA (by acetyl-CoA synthetase) and thence to fluorocitrate (by citrate synthase) before it can act as a potent metabohc inhibitor of the aconitase reaction as well as citrate transport. Submicromolar concentrations of ( )-erythro-Q iOTOcitTate can irreversibly inhibit citrate uptake by isolated brain mitochondria. 

In the past decade, a few examples of benzoannulated carbazole ring systems were found in nature as marine products. In 1993, Chan et al. reported a novel marine benzocarbazole alkaloid, purpurone (281) from the marine sponge lotrochota sp. in its racemic form. Purpurone, as indicated by its name, is purple in color. This represents the first example of a benzocarbazole alkaloid with a biphenylene quinone methide functionality. The isolate showed ATP-citrate lyase (ACL) inhibitory activity (247). 

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