Accurate quantitation of protein expression and site-specific phosphorylation

摘要: A mass spectrometry-based method is described for simultaneous identification and quantitation of individual proteins determining changes in the levels modifications at specific sites on proteins. Accurate achieved through use whole-cell stable isotope labeling. This approach was applied to detection abundance differences present wild-type versus mutant cell populations vivo phosphorylation PAK-related yeast Ste20 protein kinase that depend specifically G1 cyclin Cln2. The general affords a quantitative description cellular level expression modification, thus providing information critical understanding complex biological phenomena.