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At least 37 records · Page 2Linked to original sources
PubMed1986

Resistance of horse alpha 1-proteinase inhibitor to perchloric acid denaturation and a simplified purification procedure resulting therefrom.

Addition of perchloric acid (6.4% w/v final concentration) to horse alpha 1-proteinase inhibitor or to horse plasma neither precipitated nor inactivated alpha 1-proteinase inhibitor. None of the isoinhibitors of alpha 1-proteinase inhibitor was altered by dilute perchloric acid. This unexpected behavior led to a simplified procedure for the purification of horse alpha 1-proteinase inhibitor, consisting of removal of the bulk of plasma proteins, by perchloric acid precipitation and by gel filtration on Sephadex G-75 and G-200. The resulting preparations of alpha 1-proteinase inhibitor were immunogenically pure. The simplified purification procedure permitted the immunochemical comparison of the isoinhibitors of alpha 1-proteinase inhibitor, which proved to be immunologically identical.

Animals↗
PubMed2004

Proton dynamics in the perchloric acid clathrate hydrate HClO4.5.5H2O.

In the perchloric acid clathrate hydrate HClO4.5.5H2O, the perchlorate anions are contained inside an aqueous host crystalline matrix, positively charged because of the presence of delocalized acidic protons. Our experimental results demonstrate that the microscopic mechanisms of proton conductivity in this system are effective on a time scale ranging from nanosecond to picosecond. In the present paper, we discuss more specifically on the relaxation processes occurring on a nanosecond time scale by combining high-resolution quasielastic neutron scattering and 1H pulse-field-gradient nuclear magnetic resonance experiments. The combination of these two techniques allows us to probe proton dynamics in both space and time domains. The existence of two types of proton dynamical processes has been identified. The slowest one is associated to long-range translational diffusion of protons between crystallographic oxygen sites and has been precisely characterized with a self-diffusion coefficient of 3.5 x 10(-8) cm2/s at 220 K and an activation energy of 29.2+/-1.4 kJ/mol. The fastest dynamical process is due to water molecules' reorientations occurring every 0.7 ns at 220 K with an activation energy of 17.4+/-1.5 kJ/mol. This powerful multitechnique approach provides important information required to understand the microscopic origin of proton transport in an ionic clathrate hydrate.

Journal Article↗
PubMed1993

Rapid purification and direct microassay of calbindin9kDa utilizing its solubility in perchloric acid.

The 9 kDa calcium-binding protein, calbindin9kDa, was found to be soluble in 7% (v/v) perchloric acid. Calbindin9kDa was easily purified from rat duodenum in 1 day with perchloric acid precipitation followed by reverse-phase h.p.l.c. The yield was 21.4 +/- 2.3 nmol/g wet weight of tissue (mean +/- S.E.M.; n = 3) from normally fed 7-8-week-old rats (approx. 70% recovery). The purification was also effective with rabbit duodenum calbindin9kDa, but not with various other EF-hand calcium-binding proteins tested in the rat. Several criteria (h.p.l.c., u.v. spectrum, denaturing two-dimensional PAGE, N-terminal sequencing) indicated that the rat calbindin9kDa was purified to homogeneity and was not affected by proteolysis. High-affinity calcium-binding properties were retained and no evidence of isoforms or charge modification was observed. Residue 59, identified as Asn (not Asp as previously reported), was fully amidated. When adopted as a microassay with isocratic h.p.l.c., the perchloric acid procedure enabled rapid (less than 6 min) and direct (peptide bond absorbance) quantification of less than 1 pmol of calbindin9kDa. This new approach to purification and assay will be of particular utility for investigations of calbindin9kDa in previously intractable low-abundance sources (e.g. cultured cells).

Amino Acid Sequence↗
PubMed2003

Purification and characterization of perchloric acid soluble protein from rat lung.

We isolated a perchloric acid soluble protein from the post-mitochondria supernatant fraction of the rat lung and designated it as RLu-PSP1. The protein is soluble in 5% perchloric acid and was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. The amino acid sequence of RLu-PSP was identical with that of rat liver PSP (RL-PSP). RLu-PSP inhibited protein synthesis in a rabbit reticulocyte lysate system. It was expressed mainly in cytoplasm of bronchioles and alveolar epithelial cells of the lung from 60-day-old rats. In 15-day-old rat embryos, the epithelial-lining of the terminal buds of the respiratory tree was immunopositive. The expression of RLu-PSP increased from the embryonic 15th day to the postnatal 40th day. This is the first report on the presence of a PSP in rat lung and on its involvement in the regulation of cellular growth and differentiation.

Amino Acid Sequence↗
PubMed1984

NMR study of in vivo RIF-1 tumors. Analysis of perchloric acid extracts and identification of 1H, 31P and 13C resonances.

Perchloric acid extracts of radiation-induced fibrosarcoma (RIF-1) tumors grown in mice have been analyzed by multinuclear NMR spectroscopy and by various chromatographic methods. This analysis has permitted the unambiguous assignment of the 31P resonances observed in vivo to specific phosphorus-containing metabolites. The region of the in vivo spectra generally assigned to sugar phosphates has been found in RIF-1 tumors to contain primarily phosphorylethanolamine and phosphorylcholine rather than glycolytic intermediates. Phosphocreatine was observed in extracts of these tumor cells grown in culture as well as in the in vivo spectra, indicating that at least some of the phosphocreatine observed in vivo arises from the tumor itself and not from normal tissues. In the 31P-NMR spectra of the perchloric acid extract, resonances originating from purine and pyrimidine nucleoside di- and triphosphate were resolved. HPLC analyses of the nucleotide pool indicate that adenine derivatives were the most abundant components, but other nucleotides were present in significant amounts. The 1H and 13C resonance assignments of the majority of metabolites present in RIF-1 extracts have also been made. Of particular importance is the ability to observe lactate, the levels of which may provide a noninvasive measure of glycolysis in these cells in both the in vitro states. In addition, the aminosulfonic acid, taurine, was found in high levels in the tumor extracts.

Animals↗
PubMed2001

Development and validation of a nonaqueous titration with perchloric acid to determine sparfloxacin in tablets.

A simple, rapid and inexpensive method for the determination of sparfloxacin in tablets is described. The procedure is based on the use of volumetric dosage in a nonaqueous medium in glacial acetic acid with 0.1 M perchloric acid. The method validation yielded good results and included precision and accuracy. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay.

Anti-Infective Agents↗
PubMed1986

31P nuclear magnetic resonance analysis of lung cancer: the perchloric acid extract spectrum.

31P-NMR spectra were obtained from the perchloric acid extracts of normal lung and lung cancer tissues obtained at surgery, and from extracts of neoplastic cells cultured in vitro. The perchloric acid extract of lung cancer tissue gave rise to a signal whose chemical shift was 3.2 ppm at pH 8.0. This signal was not observed in the extract of normal tissue of the lung from the same patient. The compound giving this signal was identified as phosphorylcholine.

Adenoviridae↗
PubMed1989

Graphite-furnace atomic absorption spectrometric determination of lead, cadmium, cobalt and nickel in infant formulas and evaporated milks after nitric-perchloric acid digestion and coprecipitation with ammonium pyrrolidine dithiocarbamate.

A graphite-furnace atomic absorption method, developed for lead and cadmium, was modified to enable simultaneous determination of lead, cadmium, cobalt and nickel in infant formulas and evaporated milks. The method was assessed on the basis of analytical quality assurance results during routine analysis of samples. Detection limits (ng g-1 based on 10 g sample size for ready-to-use formulas) were 0.04-0.21 for lead, 0.004-0.015 for cadmium, 0.04-0.2 for cobalt and 0.06-0.26 for nickel. Within-series repeatability and day-to-day reproducibility (among series) coefficients of variation (CVs) were, respectively, 11.7 and 16% for lead, 2.5 and 7.5% for cadmium, 7.2 and 18.8%for cobalt, and 8.1 and 8.6% for nickel at respective concentrations of 1.89, 0.40, 1.25 and 11.8 ng g-1.

Animals↗
PubMed1978

Extraction of skin test activity from Coccidioides immitis mycelia by water, perchloric acid, and aqueous phenol extraction.

Water, perchloric acid extracts, and fractions of partially defatted whole mycelia of Coccidioides immitis contained delayed skin test activity when tested in C. immitis-infected guinea pits. Aqueous phenol extraction of these fractions resulted in partitioning of activity between aqueous-soluble and phenol-soluble fractions; activity was found to be water soluble after removal of phenol by extensive dialysis. Highest specific activity skin test antigen was invariably found in the phenol-soluble phase, water-soluble fraction. Material of equivalent activity could also be extracted directly from the defatted mycelia. Skin test active fractions contained glucose, mannose, 3-O-methylmannose, glucosamine, and amino acids.

Animals↗
PubMed1995

An ion-pairing high-performance liquid chromatographic method for the direct simultaneous determination of nucleotides, deoxynucleotides, nicotinic coenzymes, oxypurines, nucleosides, and bases in perchloric acid cell extracts.

An ion-pairing high-performance liquid chromatographic method for the direct and simultaneous determination of nucleotides, deoxynucleotides, cAMP, nicotinic coenzymes, oxypurines, nucleosides, and bases in perchloric acid cell extracts is presented. By using an Alltima C-18, 250 x 4.6-mm, 5-microns particle size column, a high resolution of 38 acid-soluble compounds, including ATP, GTP, dTTP, CTP, UTP, ADP, GDP, dTDP, CDP, UDP, dATP, dGTP, dCTP, dUTP, dADP, dGDP, dCDP, dUDP, and cAMP, is obtained. Elution is performed with a step gradient from buffer A (consisting of 10 mM tetrabutylammonium hydroxide, 10 mM KH2PO4, 0.25% methanol, pH 7.00) to buffer B (consisting of 2.8 mM tetrabutylammonium hydroxide, 100 mM KH2PO4, 30% methanol, pH 5.50). Perchloric acid extracts of resting and phytohemagglutinin-stimulated human lymphocytes were analyzed. Data indicate that this chromatographic method offers, for the first time to the best of our knowledge, the possibility of simultaneously determining di- and triphosphate nucleosides and their corresponding deoxynucleosides without any chemical manipulation of samples except for perchloric acid deproteinization. Hence, the present HPLC assay minimizes the risks of modification or loss of metabolite concentration and allows one to obtain, with a single chromatographic run, the complete pattern of those metabolites which are known to be involved in energy metabolism and in DNA and RNA synthesis, resulting therefore of great advantage in cell biology studies.

Cell Extracts↗
PubMed1992

Abrogation of c-MYC protein degradation in human lymphocyte lysates by prior precipitation with perchloric acid.

Conventional lysis buffers, though containing cocktails of protease inhibitors, did not prevent the degradation of c-MYC recombinant protein added immediately prior to lysis to cell pellets from human mixed lymphocyte cultures. Treatment of the cells with 4.2% perchloric acid, however, prevented protein degradation and facilitated the detection of c-MYC protein by Western blotting even in unstimulated lymphocytes, where previously it had been reported to be undetectable or barely detectable using this technique. PHA stimulation of lymphocytes induced an approximately six fold increase in measured c-MYC protein within 5 h if cell extracts were prepared using perchloric acid precipitation. However, using conventional lysis buffer the proto-oncogene protein was undetectable until 48-72 h after mitogen addition. Pretreatment with perchloric acid may be useful for Western blotting analysis of protein in other systems where it may be desirable to dispense with the use of toxic protease inhibitors or where these may be incompletely effective.

Blotting, Western↗
PubMed1991

[Study of human muscle biopsies with muscle glycogen storage diseases using 1H nuclear magnetic resonance spectroscopy (NMRS)--analysis of perchloric acid extracts of muscles].

Muscle metabolites of perchloric acid extracts in human muscle biopsies including the cases with muscle glycogen storage diseases (GSD) were analyzed using 1H NMR spectroscopy. Several metabolites such as lactate, pyruvate, creatine, phosphocreatine, acetate, alanine, carnitine and glycogen were recognized. The cases with GSD III and GSD V showed two broad signals at 3.60 and 3.85 ppm which were considered to be the proton signals from the accumulated glycogen. However, in GSD III, the signal at 3.60 ppm was high compared with that at 3.85 ppm suggesting that glycogen was increased in its degree of branching joined by alpha-1,6 linkage. These data suggest that 1H NMR spectroscopy is a useful and simple technique for analysis of muscle glycogen storage diseases as well as lipid myopathies.

Adult↗