S. Klumpp and J. Krieglstein: Perspective: Reversible phosphorylation of histidine residues in proteins from vertebrates. Sci. Signal. (2009) A victim of cancer, Susanne Klumpp passed away on June 17, 2009. With this initative, her former group, the university and her collaborators made an effort to keep PHP alive.Beside its importance in biochemistry PHP has been shown to be valuable as high mass calibrant in MALDI-TOF MS (ASMS 2011).MALDI-TOF high mass calibration up to 200 kDa using human recombinant 16 kDa protein histidine phosphatase aggregates.(2011) PlosOne 6,8 e23612; K. Ludwig, S. Habbach, S. Klumpp, J. Krieglstein, S. König >> Service>> PublikationenFor many years it was accepted that the phosphorylation of proteins on histidine residues for the regulation of cellular processes is only of importance in procaryotes. In 1994, in the laboratory of M. Simon at CalTech, Susanne Klumpp discovered protein histidine phosphatase activity in bovine liver.In the following years, and in particular with her group at the university of Münster, she characterized a number of aspects with respect to PHP including its structure.