Biology subjects

Rzagalinski, I.

Publications and source records attributed to Rzagalinski, I..

2 recordsLinked to original sources

bioRxiv2021

FastCAT accelerates absolute quantification of proteins by using multiple short non-purified chimeric standards

Absolute (molar) quantification of clinically relevant proteins determines their reference values in liquid and solid biopsies. FastCAT (for Fast-track QconCAT) method employs multiple short (<50 kDa) stable-isotope labeled chimeric proteins (CPs) composed of concatenated quantotypic (Q-) peptides representing the quantified proteins. Each CP also comprises scrambled sequences of reference (R-) peptides that relate its abundance to a single protein standard (BSA). FastCAT not only alleviates the need in purifying CP or using SDS-PAGE, but also improves the accuracy, precision and dynamic range of the absolute quantification by grouping Q-peptides according to the expected abundance of target proteins. We benchmarked FastCAT against the reference method of MS Western and tested it in the direct molar quantification of neurological markers in the human cerebrospinal fluid at the low ng/mL level.

biochemistry↗

bioRxiv2021

Median based absolute quantification of proteins using Fully Unlabelled Generic Internal Standard

By reporting molar abundances of proteins, absolute quantification determines their stoichiometry in complexes, pathways or networks. Typically, absolute quantification relies either on protein-specific isotopically labelled peptide standards or on a semi-empirical calibration against the average abundance of peptides chosen from arbitrary selected proteins. In contrast, a generic protein standard FUGIS (for Fully Unlabelled Generic Internal Standard) requires no isotopic labelling, chemical synthesis or external calibration and is applicable to quantifying proteins of any organismal origin. The median intensity of peptide peaks produced by the digestion of FUGIS is used as a single point calibrant to determine the molar abundance of any co-digested protein. Powered by FUGIS, median based absolute quantification (MBAQ) outperformed other available methods of untargeted proteome-wide absolute quantification.

biochemistry↗