Abstract: The invention relates to a method for the determination of an MRM or SRM assay for a protein of interest, a peptide of interest, or a group of proteins/peptides of interest or a whole proteome. It essentially includes the following steps: (1) a list of proteins of interest is selected and for each member at least one or a list of candidate proteotypic peptides is derived (2) this at least one peptide is synthesized/generated essentially without subsequent purification; (3) this at least one unpurified peptide is analyzed by selected reaction monitoring (SRM) preferably coupled to liquid chromatography (LC-SRM) or analogous techniques; (4) validation and/or optimisation of the corresponding assay of the at least one peptide with determination of the SRM coordinates for a peptide/protein of interest and/or of a regulator of interest is achieved.