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Detection of 22kDa and 20kDa GH Proteoforms in Human Plasma by LC-MS/MS

Such-Sanmartín et al., Biochim Biophys Acta. (2014) - PMID: 25556001

Product(s) used in this publication:  SpikeTides™ - Proteomics Peptide Standards

Abstract:

Human growth hormone (GH) is suspected to be widely and illegally used in sport to improve athletes' performance. For the detection of GH abuse, blood samples are screened for abnormal ratios between the 22 and 20 kDa GH proteoforms that demonstrate the administration of the synthetic hormone. Current detection methods are based on classical immunoassays as they provide sufficient sensitivity for the detection of GH proteoforms. These antibody based methods, however, suffer from unclear selectivity and potential cross-reactivity towards similar proteins. For unambiguous GH detection, we report a Mass Spectrometry ImmunoAssay (MSIA) that first enriches GH from plasma with an antibody of relatively low specificity, and subsequently quantifies the 22 and 20 kDa proteoforms by Selected Reaction Monitoring (SRM) LC-MS/MS analysis. This method proved superior to an antibody-free strategy based on GH purification by protein precipitation. Using GH-MSIA we successfully quantified the 22/20 kDa GH ratio in post-exercise capillary plasma extracted from two individuals. This GH-MSIA is applicable to anti-doping and GH-related disease analysis.

Copyright © 2014 Elsevier B.V. All rights reserved.

KEYWORDS:

Antibody purification; Blood; Growth hormone; LC-MS/MS; Mass spectrometric immunoassay; Protein precipitation

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