scholarly journals False Biomarker Discovery due to Reactivity of a Commercial ELISA for CUZD1 with Cancer Antigen CA125

2014 ◽  
Vol 60 (2) ◽  
pp. 381-388 ◽  
Author(s):  
Ioannis Prassas ◽  
Davor Brinc ◽  
Sofia Farkona ◽  
Felix Leung ◽  
Apostolos Dimitromanolakis ◽  
...  
Keyword(s):  
Biomarker Discovery ◽  
Size Exclusion ◽  
Ductal Adenocarcinoma ◽  
Elisa Assay ◽  
Expression Systems ◽  
Cancer Antigen 125 ◽  
Cancer Antigen ◽  
Specific Proteins ◽  
Size Exclusion Hplc

Abstract BACKGROUND By using proteomics and bioinformatics, we have previously identified a group of highly pancreas-specific proteins as candidate pancreatic ductal adenocarcinoma (PDAC) biomarkers. With the use of commercially available ELISAs, the performance of some of these candidates was initially evaluated in a relatively small serum cohort (n = 100 samples). This phase revealed that CUB and zona pellucida-like domains protein 1 (CUZD1) may represent a new, promising PDAC biomarker. METHODS We performed detailed experiments to investigate the specificity of the commercial CUZD1 ELISA assay. CUZD1 was expressed in house in both bacteria and yeast expression systems. Recombinant CUZD1 and biological samples containing CUZD1, as well as commercial CUZD1 ELISA standards, were analyzed by Western blot, size exclusion HPLC, and mass spectrometry (LC-MS Orbitrap). RESULTS We confirmed that instead of CUZD1, the commercial assay is recognizing a nonhomologous, known cancer antigen [cancer antigen 125 (CA125)]. CONCLUSIONS We conclude that poor characterization of commercial ELISA assays is a factor that could lead to false biomarker discovery. To our knowledge, this is the first report documenting that a commercial ELISA marketed for one analyte (CUZD1) may, in fact, recognize a different, nonhomologous antigen (CA125).

scholarly journals Purification and characterization of cystatin from duck egg white.

1995 ◽  
Vol 42 (3) ◽  
pp. 351-356 ◽  
Author(s):  
M Warwas ◽  
J Gburek ◽  
J Osada ◽  
K Gołab
Keyword(s):  
Egg White ◽  
Amino Acid Sequences ◽  
Size Exclusion ◽  
Molecular Forms ◽  
Sds Page ◽  
Peptidase Inhibitor ◽  
Size Exclusion Hplc ◽  
Duck Egg ◽  
Chicken Cystatin

It is the second peptidase inhibitor, after ovostatin, which showing the same antipapain activity in egg white in different avian species implies differences in amino-acid sequences. Cystatin from duck egg white was purified by carboxymethylpapain affinity chromatography and size-exclusion HPLC. The purified inhibitor which showed partial identity in the immunodiffusion test with chicken egg white cystatin, had an apparent molecular mass of 9.3 kDa as determined by SDS/PAGE. IEF analysis revealed five molecular forms of pI in the range 7.8-8.4. The obtained cystatin was neither glycosylated nor phosphorylated as it is in the case of chicken cystatin. The determined Ki (0.005 +/- 0.001 nM) was similar to that reported for human and chicken cystatin C.

Characterization of Polymerized Polyphenols by Size-exclusion HPLC

2002 ◽  
Vol 66 (9) ◽  
pp. 1972-1975 ◽  
Author(s):  
Akio YANAGIDA ◽  
Toshihiko SHOJI ◽  
Tomomasa KANDA
Keyword(s):  
Size Exclusion ◽  
Size Exclusion Hplc

scholarly journals Isolation and characterization of a polymerized prion protein

2002 ◽  
Vol 364 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Bao-Yuan LU ◽  
Jui-Yoa CHANG
Keyword(s):  
Prion Protein ◽  
Cd Spectroscopy ◽  
Reversed Phase ◽  
Size Exclusion ◽  
Proteinase K ◽  
Guanidinium Chloride ◽  
Isolation And Characterization ◽  
Size Exclusion Hplc ◽  
Β Sheet

A polymerized form of recombinant mouse prion protein (mPrP) domain 23–231 [mPrP-(23–231)], designated mPrP-z, was generated at acidic pH (pH 2–5) in the presence of selected concentrations of denaturant (2M guanidinium chloride or 5M urea). This isoform of mPrP is stable in acidic solution after removal of denaturant. It can be isolated and purified using reversed-phase HPLC or size-exclusion HPLC. mPrP-z bears structural properties that partially resemble those of scrapie prion. Unlike the native mPrP-(23–231) (mPrP-N), mPrP-z exhibits a high content of β-sheet structure, as shown by CD spectroscopy, and exists as an oligomer with an approximate molecular mass of 340000Da, as measured by light scattering. However, similarly to mPrP-N, mPrP-z contains the intact disulphide bond and is sensitive to digestion by proteinase K.

Quantitative characterization of oligomeric state of G-quadruplex antithrombin aptamers by size exclusion HPLC

2019 ◽  
Vol 29 (4) ◽  
pp. 424-425 ◽  
Author(s):  
Rugiya R. Alieva ◽  
Elena G. Zavyalova ◽  
Vadim N. Tashlitsky ◽  
Alexey M. Kopylov
Keyword(s):  
Size Exclusion ◽  
Oligomeric State ◽  
Quantitative Characterization ◽  
G Quadruplex ◽  
Size Exclusion Hplc

Removal of Hydrophobic and Hydrophilic Constituents by Anion Exchange Resin

1999 ◽  
Vol 40 (9) ◽  
pp. 207-214 ◽  
Author(s):  
J.-P. Croué ◽  
D. Violleau ◽  
C. Bodaire ◽  
B. Legube
Keyword(s):  
Molecular Weight ◽  
Anion Exchange ◽  
Water Source ◽  
Atomic Ratio ◽  
Size Exclusion ◽  
Salting Out ◽  
Anion Exchange Resins ◽  
Hydrophilic Character ◽  
Exchange Resins

The objective of this work was to compare the affinity of well characterized NOM fractions isolated from two surface waters with strong (gel matrix and macroporous matrix) and weak anion exchange resins (AER) using batch experiment conditions. The structural characterization of the fraction of NOM has shown that the higher the hydrophilic character, the lower the C/O atomic ratio, the lower the SUVA, the lower the aromatic carbon content and the lower the molecular weight. In general (not always), strong AER was more efficient to remove DOC than weak AER. For the same water source (Suwannee River), the higher the molecular weight of the NOM fraction, the lower the affinity with AER. Increasing the ionic strength favored the removal of the hydrophobic NOM fraction (“salting out” effect) while increasing the pH apparently reduced the removal of the hydrophilic NOM fraction. Results were discussed in terms of size exclusion, adsorption, anion exchange and also hydrophobic/hydrophilic repulsion.

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