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Results for “PERCHLORIC ACIDS”

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At least 19 recordsLinked to original sources
PubMed1989

Influence of trace metals on serum total sialic acids and perchloric acid--soluble proteins and sialic acids in mice.

Male Swiss mice were exposed to a single LD50 (75%; i.p.) of mercury, zinc, lead and manganese to determine their influence on serum sialic acid and protein levels after a refractory period of 48 h. They significantly elevated, in different proportions, the serum levels of total and perchloric acid (PCA)-soluble sialic acids (biological marker) and PCA-soluble proteins, thus indicating their toxicity.

Animals↗
PubMed1990

Colorimetric micromethods for glutaraldehyde determination by means of phenol and sulfuric acid or phenol and perchloric acid.

Aqueous micromolar solutions of glutaraldehyde produce a yellow color when treated with 20% phenol in ethanol followed by concentrated sulfuric acid or with phenol in 70% perchloric acid. The absorbance at 482 or 479 nm, respectively, is linearly related to the glutaraldehyde concentration. Of the two methods developed, the sulfuric acid-phenol assay gives a higher sensitivity and the perchloric acid-phenol assay allows the determination of glutaraldehyde in the presence of sugars and proteins.

Aldehydes↗
PubMed1978

Extraction of CEA from tumour tissue, foetal colon and patients' sera, and the effect of perchloric acid.

The use of perchloric acid and water for the extraction of CEA from tumour and foetal tissues has been investigated. In the case of tumour, lower recoveries of CEA were obtained from perchloric acid extracts than from aqueous extracts of the same tissue. CEA has also been extracted with 3M KCl solution from insoluble perchloric acid residues of tumour homogenates and cancer patients' serum. Whilst a large proportion of CEA activity recovered from tumour was associated with the perchloric acid residue, the corresponding amounts from serum were very small. CEA elution volumes for each extract, obtained by assay of Sephadex G-200 column fractions, showed significant heterogeneity in molecular size. The purified CEA pools also showed quantitative variations in the binding profiles on Con A-Sepharose. It has been shown that perchloric acid modifies the carbohydrate in CEA, thus altering its Con A-binding properties. Preliminary experiments with foetal colon have demonstrated that, unlike colorectal CEA, a significant proportion of foetal CEA was not bound to ConA. Comparative immunodiffusion showed immunological identity of CEA from the various extracts, although the purified aqueous extract produced an additional precipitin reaction, indicating a second antigen which is relatively unstable or less soluble in perchloric acid.

Bronchial Neoplasms↗
PubMed1981

Mechanisms of hydrolysis of adenosine 5'-triphosphate, adenosine 5'-diphosphate, and inorganic pyrophosphate in aqueous perchloric acid.

The acid-catalyzed hydrolysis of adenosine 5'-triphosphate (ATP) has been found to give rise both to adenosine 5'-diphosphate (ADP) and inorganic phosphate and to adenosine 5'-phosphate (AMP) and inorganic pyrophosphate. Kinetic and isotope studies on the mechanism of hydrolysis of ATP therefore depend on a knowledge of the mechanism of hydrolysis of the polyphosphate products, ADP and inorganic pyrophosphate. The latter reactions have been studied over the acidity range 1--5 M perchloric acid at 25 degrees C while the more complex problem of the hydrolysis of ATP has been followed at a single acidity (3 M perchloric acid). The positions of bond fission have been determined for both ATP and ADP.

Adenosine Diphosphate↗
PubMed1998

Purification, characterization and differentiation-dependent expression of a perchloric acid soluble protein from rat kidney.

We have recently reported the presence of a novel perchloric acid soluble protein in rat liver (PSP1) that inhibits cell-free protein synthesis in a rabbit reticulocyte system. While studying the perchloric acid soluble proteins from different tissues of rats, we found that the kidney protein cross-reacted with antibody against the PSP1. In this investigation, we have purified a perchloric acid soluble protein from the rat kidney and studied its characterization and expression. The protein extracted from the postmitochondrial supernatant fraction with 5% perchloric acid was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. By immunoscreening with the rabbit antisera against the PSP1, we detected a cDNA that contained an open reading frame of 411 bp, encoding a 137 amino-acid protein with a molecular mass of 14,149 daltons. The deduced amino acid sequence was completely identical with that of PSP1 from rat liver. The perchloric acid soluble protein from rat kidney (K-PSP1) also inhibited cell-free protein synthesis in the rabbit reticulocyte lysate system in a different manner than RNase A. Immunohistochemistry showed that the expression of K-PSP1 increased from fetal 17th day to postnatal 4th week, and it remained almost the same until the 7th week of postnatal age. Furthermore, the expression of K-PSP1 in the kidney of the nephrotic rat model was shown to be differentiation dependent. On the other hand, the expression of K-PSP1 in renal tumor cells was downregulated as compared with intact tissue. These results suggest that the expression of K-PSP1 is regulated in a differentiation-dependent manner in the kidney.

Amino Acid Sequence↗
PubMed1991

Purification of apyrase from yellow lupin cotyledons after extraction with perchloric acid.

Neutralized 1 M perchloric acid (PCA) extracts of yellow lupin (Lupinus luteus) seedling cotyledons contain considerable amounts of apyrase (EC 3.6.1.5). Investigators who use PCA extraction for the estimation of nucleotide levels, particularly in plant tissues, should be aware of this danger. Only when the material is treated with 1.8-2 M PCA are the extracts obtained free of apyrase activity. Chromatography of neutralized 1 M extracts obtained from 7-day-old seedling cotyledons on DEAE-Sephacel and Sephadex G-100 yields almost homogeneous apyrase that shows a band of M(r) 51,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. The molecular weight of the native enzyme is also about 51,000. The apyrase preparation is free of nonspecific phosphatases, nucleotidases, and adenosine nucleosidase, as well as dinucleoside polyphosphate-degrading enzymes. The apyrase exhibits a broad pH optimum between 6 and 8. Mg2+ and Ca2+ are required for maximum activity; Zn2+ and Mn2+ are less effective and Co2+, Ni2+, and Cd2+ are without effect. The Km values for ATP and ADP are about 20 microM. All common 5'-nucleoside tri- and diphosphates as well as adenosine 5'-tetraphosphate are substrates.

Adenine Nucleotides↗
PubMed1997

Short term storage of samples containing monoamines: ascorbic acid and glutathione give better protection against degradation than perchloric acid.

In order to study the protection of monoamines from degradation during short-time storage, the effect of three different antioxidants on the degradation of dopamine, dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5-HIAA) was analyzed after 5 and 20 h. The results showed that dopamine was still quite stable after 20 h storage at room temperature, but that about 95% of 5-HIAA had disappeared. The best protection against degradation of all three substances was achieved when 15% v/v of a solution containing 1-2 mM ascorbic acid or 40 mM glutathione was added to the sample, resulting in near 100% protection after 20 h. Perchloric acid actually accelerated the degradation of 5-HIAA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1986

Perchloric acid interference in enzymatic-fluorimetric-continuous-flow assay methods for measuring glucose, lactate, pyruvate, alanine, glycerol, and 3-hydroxybutyrate in blood.

Perchloric acid is commonly used to denature and precipitate proteins in samples before various metabolites are measured in tissue, blood, and other body fluids. However, perchloric acid can interfere in the analytical process, possibly by inhibiting the enzymes used. We have determined the effects of perchloric acid on measurements of glucose, lactate, pyruvate, alanine, glycerol, and 3-hydroxybutyrate in blood by enzymatic-fluorimetric-continuous-flow assays. There was a net increase or decrease in the apparent concentration of some of these metabolites when the perchloric acid concentration in the samples differed from that of the reference standards-some of these differences were due to the concentration of perchlorate ion and some to the pH of the acid extracts. The results show the need either to add a fixed amount of blood to perchloric acid or to neutralize and remove the perchlorate.

3-Hydroxybutyric Acid↗
PubMed1975

Rapid radioimmunoassay of carcinoembryonic antigen (CEA) in ultrafiltered perchloric acid extracts: results of a clinical survey.

Perchloric acid treatment of the carcinoembryonic antigen (CEA) results in subunits of approximate mol. wt 40 000 to 50 000 with different electrophoretic mobilities and amtogenic deficiences as demonstrated by immunoelectrophoresis. An improved radioimmunoassay is described for the quantitation of CEA using rapid ultrafiltration of serum or plasma extracts. The assay was designed to take into account the changes CEA undergoes during perchloric acid extraction. Absorption of antibodies against a crossreacting non-specific antigen from CEA antiserum did not improve the specificity of the radioimmunoassay as was shown by clinical use of the test in almost 1800 patients.

Animals↗