HIGH-THROUGHPUT MEASUREMENT OF PROTEIN TURNOVER IN PLANTS USING STABLE ISOTOPE LABELING COUPLED WITH LC-MS/MS ANALYSIS

摘要

A model of peptide distributions as mixed beta-binomial distributions, which were then fitted by maximum likelihood estimation proved to be successful for the estimation of protein turnover. Labeling with 15N was found to be generally better than using ~(13)CO_(2) for the purpose of protein turnover measurement due to the fact that the resulting peptides have fewer nitrogen atoms resulting in less complex spectra. The resulting spectra allowed for more accurate maximum likelihood estimations. This approach will be optimized for proteome-wide turnover measurements under conditions where the consequences of changes in plant growth, development and adaptation to changing environmental conditions can be determined in relation to protein flux in critical pathways. A web-based program (see below) is being developed for online data analysis so that general access to the methods and their easy implementation will soon be available.