INSERM 1 article published in JoVE Biochemistry Proteome-wide Quantification of Labeling Homogeneity at the Single Molecule Level Simon Leclerc1,2, Youri Arntz2, Yuichi Taniguchi1,3 1Laboratory for Cell Systems Control, RIKEN Center for Biosystems Dynamics Research, RIKEN, 2Laboratoire de Biomatériaux et Bioimagerie, INSERM, 3PRESTO, Japan Science and Technology Agency Here, we present a protocol to assess the labeling homogeneity for each protein species in a complex protein sample at the single molecule level.