Quantification of Amyloid Precursor Protein Isoforms Using Quantification Concatamer Internal Standard
Junjun J. Chen, Meiyao M. Wang, Illarion V. Turko
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 Alzheimers 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 Alzheimers disease.
, Wang, M.
and Turko, I.
Quantification of Amyloid Precursor Protein Isoforms Using Quantification Concatamer Internal Standard, Analytical Chemistry, [online], https://doi.org/10.1021/ac3033239
(Accessed December 3, 2023)