Angiostatin is a naturally occurring protein found in several animal species, including humans.
[5] Angiostatin is produced, for example, by autoproteolytic cleavage of plasminogen, involving extracellular disulfide bond reduction by phosphoglycerate kinase.
Furthermore, angiostatin can be cleaved from plasminogen by different metalloproteinases (MMPs), elastase, prostate-specific antigen (PSA), 13 KD serine protease, or 24KD endopeptidase.[which?]
There is still considerable uncertainty on its mechanism of action, but it seems to involve inhibition of endothelial cell migration,[6] proliferation and induction of apoptosis.
[9] Another proposed mechanism of action is that angiostatin binds to Angiomotin (AMOT) and activating focal adhesion kinase (FAK).