Validation of recombinant human protein purified from bacteria: an important step to increase scientific rigor.

Abstract E coli is a common host for generating human recombinant proteins in in vitro studies that seek to understand the biochemical and structural properties of proteins and in drug discovery. Validation of this biological resource is crucial to avoid misinterpretations and assay interference. Here, we demonstrate the use of tandem mass spectrometry to detect inadvertent post-translational modifications on human recombinant proteins produced in E. coli. Additionally, we identified co-purified E. coli proteins orthologous to known human interacting proteins. The results confirmed the importance of mass spectrometry in validating bacterial purified recombinant proteins as part of authenticating this key biological resource.