Rubisco is a really high copy number protein in plants. How high? Many textbooks consider it a given that it is the most common protein on our planet. You can imagine how much fun it is to do plant proteomics, then, right? This is worse than albumin and transferrin in plasma samples.
Help is on the way, plant proteomics researchers! A paper currently in press at MCP by Zhang, Gao and Xing, et al., out of Texas A&M describes Polyethyleneimine (PEI) Assisted Rubisco Cleanup (PARC) and how you can get past this pesky protein and actually see something else in your proteomics samples.