Ang K1-3 is a proteolytic fragment of plasminogen containing the first three kringle structures. A specific inhibitor of endothelial cell growth and angiogenesis. More active relative to kringles 1-4. Ang K1-3 reduces endothelial cell proliferation and acts as a potent inhibitor of angiogenesis and tumor growth Synonyms: Angiostatin, Angiostatin Kringles 1-3, Ang K1-3.