Proteolytic degradation of hemoglobin by endogenous lysosomal proteases gives rise to bioactive peptides: hemorphins

Hemorphin generation by mice peritoneal macrophages has been recently repor ted, nevertheless no conclusive data exist to localize clearly the macropha ge proteolytic activity implicated in their generation. Because lysosomes a re believed to be the main site of degradation in the endocytic pathway, we have studied their potential implication in the generation of hemorphins f rom hemoglobin. When this protein is submitted to purified rat liver lysoso mes, an early generation of hemorphin-7-related peptides, detected by a rad ioimmunoassay, was observed. These peptides seemed to be relatively stable during the first hours of hydrolysis. (C) 1999 Federation of European Bioch emical Societies.