The receptor for advanced glycation end products (RACE) is a multi-ligand receptor involved in the development of diabetic complications. Although the soluble form of the extracellular domain maintains the ability to bind multi-ligands, it is unstable and degrades into several peptide species during storage. Proteolysis with thrombin or factor Xa revealed several protease sensitive sites. Most sensitive site is located between Arg228 and Val229, and peptide bond next to Arg216, Arg116, Arg114 and Trp271 are also cleaved. Seven truncated extracellular domains of RAGE were engineered in order to obtain a stable soluble fragment. RACE 143 (Ala23-Thr143) is not only protease resistant but also shows the same ligand-binding ability as that of the full-length extracellular domain. The resultant minimum RACE 143 works as a stable recognition devise to detect advanced glycation end products (AGEs). (C) 2009 Elsevier Inc. All rights reserved.