Many biological mechanisms, such as immune response, apoptosis or pathogenesis of diseases, are based on post-translational modifications of proteins. Although the technologies in proteomics have developed rapidly in the last years, until now the identification of such modified proteins suffered from a number of limitations. Particularly, the transformation of proteins by glycosylation—carbohydrates binding to single amino acids—has been widely unexplored. But exactly this process is one of the most important mechanisms for the transformation of proteins and plays an important role in the formation of organs and organisms. Errors during the protein modification or if it takes place in an unregulated way can contribute to diseases like Alzheimer's disease or Creutzfeldt–Jakob disease.

Now, scientists of the Max Planck Institute of Biochemistry in the research department "Proteomics and Signal Transduction", headed by Matthias Mann, have developed a mass spectrometry-based method that allows the identification of N-glycosylated protein sites in different tissues in a highly efficient way. The new method has enabled the identification of 6367 N-glycosylated protein sites. Furthermore, they derived novel recognition sequence patterns for N-glycosylation. The work was published in Cell (doi: 10.1016/j.cell.2010.04.012).

These findings constitute an important progress in proteomics, because they improve our understanding of the processes inside the human body. Moreover, they could play an essential role for the investigation of diseases: the scientists managed to identify some modified protein sites which are associated with different illnesses: They discovered N-glycosylated sites, unknown up to now, on proteins which play an important role in Alzheimer's disease. Because N-glycosylation is involved in many processes which are going wrong in Alzheimer's disease, scientists suspect that this type of protein modification directly causes the disease or, at least, influences its course crucially. Hence, the Max Planck scientists hope that the results of this study could contribute to the further investigation of diseases like Alzheimer's.