Proteins control life as one of the most important biomolecules – as enzymes, receptors, signal or structural building blocks. Researchers at the Max Planck Institute (MPI) of Biochemistry have for the first time uncovered the proteomes of 100 different organisms. The selected specimens come from all three domains of life: bacteria, archaeae and eukaryotes. Using mass spectrometry, 340,000 unique proteins were measured. Related proteins conserved througout evolution can now be compared quantitatively for the first time. The results were published in Nature.