ADAMTS (a disintegrin and metalloproteinase with thrombospondin motif) is a novel family of extracellular proteinases. Presently eighteen family members have been identified in the human genome. ADAMTS4 was first purified from Il-1-stimulated bovine nasal cartilage conditioned media and human ADAMTS4-cDNA was cloned from a human heart cDNA library. ADAMTS4 consists of a prodomain, a catalytic domain, a disintegrin domain, a thrombospondin type-1 motif and a Cys-rich region followed by a C-terminal sequence. The prodomain is most likely cleaved off by a furin-type enzyme before ADAMTS4 is released from cells.