Method of inhibiting activity of cell surface fibroblast activation protein alpha

The presently disclosed inventive concept(s) include inhibitors of antiplasmin cleaving enzyme (APCE) and fibroblast activation protein alpha (FAP) which can be used in various therapies related to disorders of fibrin and α2-antiplasmin and abnormal cell proliferation. The presently disclosed inventive concept(s) also include substrates of APCE and FAP, which may be used, for example, in screening methods for identifying such inhibitors. The presently disclosed inventive concept(s) further include, but are not limited to, methods of treating or inhibiting atherosclerosis and thrombus disorders by altering the ratios of types of plasma α2-antiplasmin and to methods of treating conditions involving abnormal cell proliferation such as cancers.