The hemoglobin in the red blood cells ensures that our body cells receive sufficient oxygen. When the blood pigment is broken down, heme is produced, which in turn can influence the protein cocktail in the blood. Researchers at the University of Bonn have now discovered in complex detective work that the activated protein C (APC) can be commandeered by heme. At the same time, APC can also reduce the toxic effect of heme. Perspectively, the findings may provide the basis for better diagnostic and therapeutic approaches to blood diseases. The study has been published online in advance in the journal Antioxidants & Redox Signaling. The print version will be published soon.