Quantification of Amyloid Precursor Protein Isoforms Using Quantification Concatamer Internal Standard

Published

January 2, 2013

Author(s)

Junjun J. Chen, Meiyao M. Wang, Illarion V. Turko

Abstract

It is likely that expression and/or post-translational generation of various protein isoforms can be indicative of initial pathological changes or clarifying of pathology development. However, quantification of individual protein isoforms remains a challenge, because they simultaneously possess common and unique amino acid sequences. Quantification concatamer (QconCAT) internal standards were originally proposed for a large-scale proteome quantification and represent artificial proteins that are concatamers of tryptic peptides for several proteins. We have used this basic approach to develop a QconCAT for quantification of various isoforms of amyloid precursor protein (APP). APP-QconCAT includes tryptic peptides that are common for all isoforms of APP concatenated with those tryptic peptides that are unique for specific APP isoforms. Isotope-labeled APP-QconCAT was expressed, purified, characterized and further used for quantification of total APP, APP695, and amyloid-β (Aβ) in the human frontal cortex from control and severe Alzheimer’s disease donors. The biological implications of our quantitative measurements are discussed. It is also expected that using APP-QconCAT(s) will advance our understanding of biological mechanism by which various APP isoforms involved in the pathogenesis of Alzheimer’s disease.

Citation

Analytical Chemistry

Volume

85

Issue

1

Pub Type

Journals

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DOI Link

Keywords

multiple reaction monitoring, mass spectrometry, QconCAT, isotope-labeled standard, quantification, Alzheimer's disease

Citation

Chen, J. , Wang, M. and Turko, I. (2013), Quantification of Amyloid Precursor Protein Isoforms Using Quantification Concatamer Internal Standard, Analytical Chemistry, [online], https://doi.org/10.1021/ac3033239 (Accessed December 12, 2024)