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At least 685 records · Page 38Linked to original sources
PubMed2003

Analysis of relative isotopologue abundances for quantitative profiling of complex protein mixtures labelled with the acrylamide/D3-acrylamide alkylation tag system.

The new method of analysis of relative isotopologue abundances (ARIA) applied here is based on the evaluation of total isotope patterns of tryptic protein fragments measured by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) to calculate the mixing ratios of composites consisting of stable isotope labelled and isotopically natural (unlabelled) proteins, as described in an accompanying paper in this issue. Recently, Sechi (Rapid Commun. Mass Spectrom. 2002; 16: 1416-1424) and Gehanne et al. (Rapid Commun. Mass Spectrom. 2002; 16: 1692-1698) introduced the use of differential quantitative mass analysis by MALDI-TOFMS using mixtures of standard proteins alkylated prior to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with either acrylamide (AA) or deuterium-labelled [2,3,3'-D(3)]-acrylamide (D3AA). In the present study we validate the AA/D3AA system, firstly by measuring the yield of proteins alkylated with AA, and secondly by using differential radioactive labels ((125)I and (131)I) to quantitatively establish that non-comigration in 2D-PAGE is negligible. ARIA is then applied to quantitatively estimate the relative proportions of peptides labelled with AA or D3AA in the validated system, using typical silver-stained 2D-PAGE protein spots from 2D gels loaded with 150 microg of total liver protein. The precision and limitations of ARIA quantification of peptides differentially alkylated with isotopomeric reagents are discussed.

Acrylamide↗
PubMed1975

A new two-dimensional gel electrophoresis system for the analysis of complex protein mixtures: application to the ribosome of E. coli.

A new method for two-dimensional polyacrylamide gel electrophoresis of proteins is described. The method, illustrated here by its application for the analysis of ribosomal proteins of E. coli, has a high resolving power. The proteins S15 and S16 can be resolved either following alkylation or under reducing conditions. This was not possible with urea gel systems previously employed. The method should be advantageous in the identification of the components of dimers formed with the reagent methyl 4-mercaptobutyrimidate. An additional advantage of the new method is that both dimensions are run at an acidic pH. For ribosomal proteins it is therefore unnecessary to either polymerize the protein sample in the middle of the first dimension disc gel or to electrophorese two samples with opposite polarity.

Bacterial Proteins↗
PubMed1985

An automated device for the preparation of complex reagent mixtures. The immunofluorescence tomograph.

A microcomputer-controlled device was built that automatically prepares small volumes of mixtures of up to eight reagents. The operation of the system is fast, flexible, and reliable, thus making possible the routine use of experimental protocols that require large numbers of small volume reagent samples, each having a different composition. In particular, the software we developed for this device handles the preparation of three-antibody staining solutions to be used in triple labeling immunofluorescent flow cytometry experiments that involve only two fluorochromes. In this role, the device is known as an "Immunofluorescence Tomograph."

Antibodies, Monoclonal↗
PubMed2003

Application of GRAM and TLD to the resolution and quantitation of real complex multicomponent mixtures by fluorescence spectroscopy.

The application of the generalised rank annihilation method (GRAM) and the trilinear decomposition (TLD) method to the resolution and quantitation of fluorescence excitation-emission matrices of a ternary mixture of pesticides, carbendazim, fuberidazole, and thiabendazole, with overlapped spectra is described. The results obtained with both methods are compared and evaluated using measures of similarity (correlation coefficients) between the real and estimated spectra. Both approaches have been tested using augmented data matrices containing only two samples, but none of these methods succeeded completely in resolution of the system. When TLD was applied to augmented data matrices containing more than two samples better performance was achieved. To illustrate the application of both algorithms to real samples, they were used in the analysis of water samples containing the target pesticides. Again, TLD had an advantage over GRAM because the ability to analyse data from multiple (more than two) samples simultaneously allowed the resolution of the mixtures.

Benzimidazoles↗
PubMed1988

Use of tandem mass spectrometry (MS-MS) for aldosterone assay at the nanogram level in complex biological mixtures.

Aldosterone in biological samples was measured comparatively by two methods: radioimmunoassay (RIA) and tandem mass spectrometry. The last method is described in this paper. Aldosterone was derivatized as butane boronate cyclic ester. This derivative gives an intense molecular ion under 70-eV electron impact conditions. This ion exhibits an abundant metastable decomposition in the second field free region by loss of formic acid, which can be used for the assay. A linear relationship was observed between the ionic current and the amount of aldosterone from 10 to 200 ng. A good correlation between this new method and the radioimmunological assay is observed. Aldosterone can be readily detected at the nanogram level.

Adrenal Glands↗
PubMed1993

Improvement of antisera raised against complex antigen mixtures by the use of heterologous sources of antigen for immunization.

Polyspecific antisera against antigen mixtures are important tools for many experimental purposes. However, following immunization with extracts containing a great number of different proteins, many antigens remain non-immunogenic. Therefore, the improvement of the antibody spectrum of antisera is an essential goal in maximising the power and applicability of many serological analyses. In the present report we demonstrate that the additional use of heterologous (i.e., antigenically related, but not identical) antigen mixtures for immunization increases the variety of antibodies in polyspecific antisera as well as the antibody titer against weak immunogens.

Animals↗
PubMed1982

Use of erythrocyte hemolysis kinetics in the purification of complex cardiotoxin mixtures.

A human erythrocyte hemolysis kinetic method provides a useful way to follow the purification of cobra venom cardiotoxins or other hemolytic factors. Initial rates of hemolysis, measured as hemoglobin released with time for the separated cardiotoxins from the venom of the Thailand cobra Naja naja siamensis, vary over a greater range than do other commonly used measures of their biological activity. Recovery of the hemolytic activity of the gross cardiotoxin fraction in the subsequently separated fractions has been demonstrated. The method employs submilligram quantities of mixed or purified cardiotoxins.

Animals↗