Antiplasmin-cleaving enzyme is a soluble form of fibroblast activation protein.

Circulating antiplasmin-cleaving enzyme (APCE) has a role in fibrinolysis and appears structurally similar to fibroblast activation protein (FAP), a cell-surface proteinase that promotes invasiveness of certain epithelial cancers. To explore this potential relationship, we performed comparative structure/function analyses of the 2 enzymes. APCE from human plasma and recombinant FAP (rFAP) exhibited identical pH optima of 7.