Detection and quantification of plasma amyloid-beta by selected reaction monitoring mass spectrometry.

Title
Detection and quantification of plasma amyloid-beta by selected reaction monitoring mass spectrometry.
Authors
김준석안희성조수민이지은김영수이철주
Keywords
Alzheimer's disease; Amyloid-β; Selected reaction monitoring; High pH reversed-phase liquid chromatography
Issue Date
2014-08
Publisher
Analytica chimica acta
Citation
VOL 840, 1-9
Abstract
Amyloid-β (Aβ) in human plasma was detected and quantified by an antibody-free method, selected reaction monitoring mass spectrometry (SRM-MS) in the current study. Due to its low abundance, SRM-based quantification in 10 μL plasma was a challenge. Prior to SRM analysis, human plasma proteins as a whole were digested by trypsin and high pH reversed-phase liquid chromatography (RPLC) was used to fractionate the tryptic digests and to collect peptides, Aβ1&#8211;5, Aβ6&#8211;16, Aβ17&#8211;28 and Aβ29&#8211;40(42) of either Aβ1&#8211;40 or Aβ1&#8211;42. Among those peptides, Aβ17&#8211;28 was selected as a surrogate to measure the total Aβ level. Human plasma samples obtained from triplicate sample preparations were analyzed, obtaining 4.20 ng mL&#8722;1 with a CV of 25.3%. Triplicate measurements for each sample preparation showed CV of <5%. Limit of quantification was obtained as 132 pM, which corresponded to 570 pg mL&#8722;1 of Aβ1&#8211;40. Until now, most quantitative measurements of Aβ in plasma or cerebrospinal fluid have required antibody-based immunoassays. Since quantification of Aβ by immunoassays is highly dependent on the extent of epitope exposure due to aggregation or plasma protein binding, it is difficult to accurately measure the actual concentration of Aβ in plasma. Our diagnostic method based on SRM using a surrogate peptide of Aβ is promising in that actual amounts of total Aβ can be measured regardless of the conformational status of the biomarker.
URI
http://pubs.kist.re.kr/handle/201004/48274
ISSN
00032670
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KIST Publication > Article
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