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PubMed1967

The proteins and protein-bound carbohydrates of the serum of the developing pig.

1. The concentrations of total nitrogen, hexosamine and protein-bound hexose and the amounts of these constituents precipitated by trichloroacetic acid were determined in the serum of pigs at various ages from 57 days after copulation to 42 days after birth. The concentrations of the same constituents were also determined in the serum of mature pigs. 2. A rise in the concentrations of total nitrogen, hexosamine and protein-bound hexose between 90 days' gestation and term was entirely due to material soluble in trichloroacetic acid. This material disappeared from the serum by 7 days after birth. 3. Electrophoresis of the serum proteins showed that the concentration of alpha(1)-globulin fell steadily during gestation, being lower at term than at 57 days' gestation. No alpha(1)-globulin was detected at 7 days of age. 4. It was concluded that high values for non-protein nitrogen in the serum of newborn piglets, determined after precipitation of the proteins with trichloroacetic acid, is largely due to the presence of one or more mucoproteins and not to alpha(1)-globulin. 5. The protein migrating in the alpha(1)-globulin position is possibly a foetal protein of the fetuin type.

Alpha-Globulins↗
PubMed1990

Effects of low and high relative molecular protein mass on four methods for total protein determination in urine.

Four commonly used methods for the determination of total protein in urine were compared. These were two biuret methods using different precipitants, a Ponceau S method and a Coomassie Brilliant Blue method. The protein content of the urines was also evaluated by sodium dodecylsulphate polyacrylamide gel electrophoresis. The biuret method with ethanolic phosphotungstic acid as precipitant correlated best with the Coomassie Brilliant Blue method (r = 0.944; p less than 0.001) but less well with the Ponceau S (r = 0.895; p less than 0.001) or biuret-trichloroacetic acid (r = 0.874; p less than 0.001) methods. For urines with normal electrophoretic protein patterns, the imprecise biuret-trichloroacetic acid method (cv = 18.5%) gave the greatest number of false high results (23 in 36 urines) as assessed by electrophoresis. False low results were common in low relative molecular mass (Mr) proteinuria, especially with the biuret-tricholoroacetic acid and Ponceau S methods. High Mr proteinuria rarely caused false low results. Discrepancies between methods appear to have resulted from incomplete precipitation of low Mr protein by trichloroacetic acid.

Azo Compounds↗
PubMed1970

Metabolism of valine by the filamentous fungus Arthrobotrys conoides.

Uptake of valine by Arthrobotrys conoides was an active process and was independent of its incorporation into cellular protein. Chemical fractionation of cells supplied with (14)C-l-valine for different time intervals revealed that the amino acid initially entered a pool of metabolic intermediates and was extractable with cold trichloroacetic acid. After a 4-min interval, some intracellular valine was incorporated into cell proteins, but most underwent metabolic transformation to a variety of products that included carboxylic acids and other amino acids. Carbon derived from valine was not localized in the lipid or nucleic acid fraction of cells, but some was completely oxidized and recovered as metabolic (14)CO(2). Autoradiograms of paper and thin-layer chromatograms of acid hydrolysates of cellular protein identified the following amino acids as having originated from valine: glutamate, aspartate, alanine, and leucine. Similar analysis of cold trichloroacetic acid extracts established that (14)C supplied as l-valine had been transformed also to alpha-ketoisovalerate, isobutyrate, propionate, succinate, malate, oxalacetate, pyruvate, and alpha-ketoglutarate. Pathways for transformation of the carbon skeleton of valine to various metabolic products are proposed.

Alanine↗
PubMed1969

The effect of magnesium ion deprivation on the synthesis of mucopeptide and its precursors in Bacillus subtilis.

1. Mg(2+) or Mn(2+) starvation causes suspensions of Bacillus subtilis strain W 23 to accumulate bound amino sugars that are soluble in trichloroacetic acid. 2. The presence of chloramphenicol or puromycin produces higher intracellular concentrations of amino sugars during Mg(2+) starvation, but neither compound can stimulate the accumulation when Mg(2+) is present. 3. The major component of the amino sugar fraction extracted from cells deprived of Mg(2+) is a nucleotide containing uridine, phosphorus, N-acetylmuramic acid, alanine, glutamic acid and alphain-diaminopimelic acid in the molar proportions of 1:2:1:3:1:1. This compound represents at least 80% of the bound N-acetylhexosamine extracted by trichloroacetic acid. 4. Studies of the binding of this nucleotide with vancomycin support the proposal that it is the mucopeptide precursor UDP-N-acetylmuramyl-l-alanyl-d-glutaminyl- alphain-diaminopimelyl-d-alanyl-d-alanine. 5. A method is described for the isolation of this material labelled with [(3)H]alphain-diaminopimelic acid. 6. When Mg(2+) is supplied to cells previously starved of Mg(2+), the accumulated pool of amino sugars rapidly decreases. 7. The biosynthesis of mucopeptide is inhibited by 35-50% under conditions of Mg(2+) starvation. The presence of EDTA increases this inhibition to 70%. The amount of N-acetylhexosamine that accumulates is balanced exactly by the associated fall in mucopeptide synthesis. 8. ;Chase' experiments show that the accumulated N-acetylhexosamine compound is utilized in mucopeptide synthesis.

Amino Sugars↗
PubMed1966

Interaction of Vi antigen with proteins.

Whiteside, Roberta E. (Boston University School of Medicine, Boston, Mass.), and Edgar E. Baker. Interaction of Vi antigen with proteins. J. Bacteriol. 92:1597-1603. 1966.-Purified Vi antigen (Vi) mixed in equal amounts with bovine serum albumin (BSA) or human gamma globulin (HGG) at pH values above 4.7 formed a complex which was not precipitated by trichloroacetic acid or tungstic acid. At pH values below 4.7, the interaction between Vi and either BSA or HGG produced insoluble complexes except when excess Vi antigen was present. When sufficient Vi was present at the lower pH values, the soluble complex was not precipitated by trichloroacetic acid. Other acid polysaccharides tested did not form trichloroacetic acid-soluble complexes with BSA. When subjected to immunoelectrophoresis, the Vi-BSA complex migrated in agar at a rate different from that of either BSA or Vi alone. The complex reacted with both Vi and BSA antiserum. The addition of either BSA or Vi antiserum to a Vi-BSA complex resulted in dissociation of the complex and precipitation of either Vi or BSA, depending upon the antiserum used. Vi antigen mixed with purified O antigen from Salmonella typhosa formed a complex which migrated in agar at a rate different from that of either component alone when subjected to immunoelectrophoresis.

Antigens↗
PubMed1998

Simplified endoproteinase assays using gelatin or azogelatin.

Endoproteinase assays with gels containing incorporated gelatin have shown that gelatin is an exceptional substrate for studying enzymes from different sources. However, due to its solubility in trichloroacetic acid, gelatin is not suited to "in-solution" assays carried out in the classic manner (by reading the absorbance of supernatants of hydrolysis reactions after the substrate has been precipitated with trichloroacetic acid). In this paper we demonstrate that gelatin can be used for such analyses by using isopropanol as precipitating reagent. Alternatively, azogelatin, which is precipitated by trichloroacetic acid, can be used. Azogelatin also serves as a very good substrate. One problem with using gelatin (or any nonderivatized protein) as substrate for measuring the activity of crude enzyme preparations is that protein contaminants in the enzyme preparation are hydrolyzed. The resulting peptides are impossible to differentiate from those released from the gelatin substrate. This problem is obviated when azogelatin is used, since its peptides are detected at 440 nm, where nonderivatized peptides do not absorb. Unlike some azo-derivatized proteins, azogelatin is soluble from pH 3.0 to 9.0. This, together with the fact that it is hydrolyzed by many different endoproteinases, makes it suitable for many applications.

Electrophoresis, Polyacrylamide Gel↗
PubMed1979

Differences in urinary trichloroethylene metabolites of animals.

Differences in urinary excretion of trichloroethylene were studied in rabbits, rats and mice. Trichloretylene (1 m mole/kg) was injected intra-peritoneally, then urinary trichloroacetic acid and trichloroethanol glucuronide were measured. The results were: 1. The ratio of total excretion of trichloroethylene metabolites to the administered trichloroethylene decreased in the order of mice, rats and rabbits. 2. The ratio of total trichloroethanol to trichloroacetic acid in urine decreased in the order of rabbits (69.2), mice (12.8) and rats (2.3). The high ratio in rabbits was due to the extremely small amount of trichloroacetic acid in the urine. 3. Differences in these two urinary metabolites in the three kinds of animals and in human subjects were discussed.

Animals↗
PubMed1995

Increased DNA-bending activity and higher affinity DNA binding of high mobility group protein HMG-1 prepared without acids.

Recently, DNA ring closure assays showed that high mobility group protein HMG-1 and its close homolog HMG-2 mediate sequence-independent DNA flexion. This DNA-bending activity appears to be central to at least some of the recently elucidated functions of HMG-1/2, such as the enhancement of progesterone receptor DNA binding. Here we show that standard purification procedures utilizing perchloric and trichloroacetic acid can produce HMG-1 significantly deficient in its abilities to bind and bend double-stranded DNA, while acid-independent methods purify HMG-1 that is superior in these respects. Significant losses of DNA ring closure activity were seen upon limited 2-5-h exposures of nonacid-purified HMG-1/2 to perchloric acid and/or trichloroacetic acid. Measurements of the apparent DNA dissociation binding constant (Kd(app)) of acid-extracted preparations of HMG-1 gave a wide range of values, and only those preparations demonstrating little DNA ring closure activity had Kd values near the previously published value (approximately 10(-6) M). The highest ring closure activities and lowest Kd(app) (< 3 x 10(-9) M) were obtained for HMG-1 purified without acids. These combined results support the use of alternative, non-acid purification procedures for preserving the DNA-bending activity of HMG-1/2 and suggest that past procedures utilizing acids have led to an underestimation of the affinity of HMG-1 for DNA.

Animals↗
PubMed1963

CONVERSION OF THE PHASE I ANTIGEN OF COXIELLA BURNETII TO HAPTEN BY PHENOL TREATMENT.

Anacker, R. L. (Rocky Mountain Laboratory, Hamilton, Mont.), W. T. Haskins, D. B. Lackman, E. Ribi, and E. G. Pickens. Conversion of the phase I antigen of Coxiella burnetii to hapten by phenol treatment. J. Bacteriol. 85:1165-1170. 1963.-Trichloroacetic acid extracts of Coxiella burnetii are converted to hapten by treatment with phenol. Such extracts react, like the original trichloroacetic acid extract, at high dilution in the complement-fixation test and produce zones of precipitate with specific antibody in gel diffusion tests; but, unlike the parent extract, injection of the phenol-treated extract neither induces resistance to challenge in guinea pigs nor antibody formation in guinea pigs, rabbits, or mice. This loss of antigenicity is correlated with removal of protein from the original product.

Animals↗