The disclosed methods relate to a strategy for producing
ground truth quantification ratios (both synthetic knockouts and simulated
dose response gradients) using synthetic peptides mixed with a human
proteome background. These, synthetic, bespoke proteins serve as a built in
quality control for
sample preparation for
proteomics workflows. Additionally, mixtures of synthetic peptides are combined to form assembled synthetic proteins that can be spiked into samples at the start of
processing (e.g.,
trypsin digesting, purification, etc.). In this way, problems in
processing methods can be discovered. Sequences can be engineered to inform how well samples are being processed.