Issue 10, 2012

MeCAT labeling for absolute quantification of intact proteins using label-specific isotope dilution ICP-MS

Abstract

Sensitive, accurate and fast absolute quantification of intact proteins is reported using metal coded affinity tags (MeCATs) combined with gel electrophoresis (GE) separation, inductively coupled plasma mass spectrometry (ICP-MS) detection and label-specific isotope dilution analysis quantification. Two different approaches were investigated concerning the introduction of the sample into ICP-MS, mineralization of the gel and direct laser ablation (LA) of the spot. Three major advantages are remarkable in the proposed method. First, not only heteroatom-containing proteins but also all labeled proteins in the sample can be absolutely quantified preparing an isotopically enriched tracer. On the other hand, highly sensitive determination in the amol range can be performed, considerably reducing the analysis time due to the straightforward measurements by ICP-MS. Furthermore, the studied method allows accurate quantifications with different sample-to-spike ratios and using stock spikes stored for months. After the first characterization using standard proteins, human serum albumin (HSA) and transferrin (Tf) were determined in human serum to test the applicability of the method to biological samples. The results show satisfactory quantifications for the studied proteins despite the difference in concentration and the similarity in migration distances.

Graphical abstract: MeCAT labeling for absolute quantification of intact proteins using label-specific isotope dilution ICP-MS

Supplementary files

Article information

Article type
Paper
Submitted
02 maj 2012
Accepted
30 jul 2012
First published
22 avg 2012

J. Anal. At. Spectrom., 2012,27, 1701-1708

MeCAT labeling for absolute quantification of intact proteins using label-specific isotope dilution ICP-MS

D. Esteban-Fernández, F. S. Bierkandt and M. W. Linscheid, J. Anal. At. Spectrom., 2012, 27, 1701 DOI: 10.1039/C2JA30137G

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