Polyclonal antibody against purified cucumisin from the Korean melon and its application: thrombolytic application

We recently bred a cucumisin-containing Korean variety of melon. However, it is not known whether the cucumisin macromolecule can pass the intestinal barrier. We developed a polyclonal antibody against cucumisin and tried to confirm whether orally administered cucumisin passes through the intestinal tract with mouse. Cucumisin was isolated and purified from the improved Korean melon by ion exchange chromatography. Protein size was estimated by SDS-PAGE and protease activity was confirmed by performing zymography and fibrin plate assay. The purified cucumisin largely comprised a native form (67 kDa) and mature form (54 kDa), and displayed fibrinolytic activity, as evident by the decomposition of gelatin and fibrin to form a clear zone. To confirm the transition to blood following the oral administration of cucumisin, a polyclonal antibody against cucumisin was produced. Use of the antibody in ELISA and immunoblotting analyses confirmed the transfer of cucumisin to the blood of cucumisin-fed mice as compared to those not fed cucumisin. Orally administered cucumisin can migrate through the intestinal barrier and into the blood. The fibrinolytic activity of cucumisin purified from the improved Korean melon might be exploited for development as a raw material for a thrombolytic drug.