Mass spectrometry metallothioneins

MTs = metallothioneins NMR = nuclear magnetic resonance pKa = negative logarithm of acid dissociation constant PMT = photomultiplier tube QITMS = quadrupole ion trap mass spectrometry SBSE = stir bar sorptive extraction SDS-PAGE = sodium dodecylsulfate polyacrylamide gel electrophoresis Se-Cis = selenocystine Se-Cys = selenocysteine Se-Et = selenoethionine Se-Hcy = seleno-homocysteine Se-Met = selenomethionine SEC = supercritical fluid chromatography TBT = tributyltin TETRA = tetramethylarsonium ion Tf = transferrin TMAsO = trimethylarsineoxide TMSe = trimethylselonium ion TOFMS = time of flight mass spectrometry USN = ultrasonic nebulizer. 

J. Zaia, D. Fabris, et al.. Monitoring metal ion flnx in reactions of metallothionein and drug-modified metallothionein by electrospray mass spectrometry, Protein Sci. 7, 2398-2404 (1998). 

Knudsen, C.B. Bjomsdottir, I. Jons, O. Hansen, S.H. Detection of metallothionein isoforms from three different species using on-line capillary electrophoresis-mass spectrometry. Anal. Biochem. 1998, 265, 167. 

The absolute amount of the element in different species can be obtained by the integration of the corresponding peaks in the chromatogram of mass flow. From recent literature, a trend can be found that the species-unspecific mode has been widely applied in measurement of different metalloproteins, such as metallothioneins (MTs)." It should be mentioned that molecular mass spectrometry is usually required to identify the analyte with the complicated matrices. 

Prange et al. analyzed the isoforms of metallothioneins in human brain cytosol with capillary electrophoresis (CE) coupled to ICP-SFMS (inductively coupled plasma-sector field mass spectrometry). In the study, three metal-lothionein isoforms were separated by CE, and the enriched isotopes of Cu, Zn, Cd, and were mixed as a specific-unspecific spiking solution finally, the Cu, Zn, Cd, and S in metallothioneins were quantified with IDA. They found that the levels of MT-3 and MT-1 were lower in the brain samples from the patients with Alzheimer s disease in comparison with the controls (see Figure 4.8). The results indicated that quantification of metalloproteins gave additional information on its relationship with Alzheimer s disease. ... 

The above methods have opened a new door to tackle quantitative proteomics by element mass spectrometry, although it is still quite difficult to quantify proteins by element mass spectrometry detection after element labeling. In fact, element labeling is not a new concept. For example, a silver saturation assay was applied for measurement of metallothionein in tissue. But this kind of metal-binding assay is based on certain properties of a protein and, being less selective, is applied mainly for a known and isolated protein. Comparatively, bi-functional chelating reagents are established in selective, reproducible reactions and thus are more suitable for protein quantification by element mass spectrometry detection. 

Profrock D., Leonhard P. and Prance A. (2003) Determination of sulfur and seleded trace elements in metallothionein-like proteins using capillary eledrophoresis hyphenated to inductively coupled plasma mass spectrometry with an odopole reaction cell. Anal. Bioanal. Chem. 377 132-139. 

Wang, Z. and Prange, A. (2002) Use of surface-modified capillaries in the separation and characterization of metallothionein isoforms by capillary electrophoresis inductively coupled plasma mass spectrometry. Anal. Chem., 74, 626-31. 

Prange, A., Schaumloffel, D., Bratter, P., Richarz, A. N., and Wolf, C. (2001) Species analysis of metallothionein isoforms in human brain cytosols by use of capillary electrophoresis hyphenated to inductively coupled plasma-sector field mass spectrometry. Fresenius J. Anal. Chem., 371, 764-74. 

Polec, K., Szpunar, J., Palacios, O., Gonzalez-Duarte, R, Atrian, S., and Lobinski, R. (2001) Investigation of metal binding by recombinant and native metallothioneins by capillary zone electrophoresis (CZE) coupled with inductively coupled plasma mass spectrometry (ICP-MS) via a self-aspirating total consumption micronebulizer. J. Anal. At. Spectrom., 16, 567-74. 

Keywords circular dichroism electronic absorption electrospray ionization mass spectrometry magnetic circular dichroism metal-thiolate cluster structures metallothionein perturbed angular correlation of y-rays spectroscopy X-ray... 

Figure 4 Quantification of separated Cd species in fish MTs (real sample) by AE-FPLC-ID-ICP-MS. Cd was used as spike. Inset shows the transformation of intensity signals into mass flow chromatogram (by means of ID equation). The quantification of Cd bound to each metalloproteins (numbered from 1 to 5) could be achieved by this technique. (Rodn guez-Cea A, Fernandez de la Campa MR, Blanco Gonzalez E, Andon B, and Sanz-Medel (2003) Metal spedation analysis in eel Anguilla anguilla) metallothioneins by anionic exchange FPLC-isotope dilution-ICP-MS. Journal of Analytical Atomic Spectrometry 18 1357-1364 reproduced from The Royal Society of Chemistry.)...

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