Mikroba endofit adalah mikroorganisme yang hidup dalam jaringan tanaman tanpa merugikan inangnya. Mereka mampu menghasilkan berbagai enzim dan metabolit bioaktif, termasuk enzim fibrinolitik yang penting untuk terapi penyakit kardiovaskular seperti trombosis. Enzim ini bekerja dengan mengaktifkan plasminogen menjadi plasmin atau langsung mendegradasi fibrin, sehingga dapat melarutkan gumpalan darah. Dibandingkan dengan sumber lain, mikroorganisme sebagai penghasil enzim fibrinolitik memiliki beberapa keunggulan seperti mudah untuk dikultivasi, produksi cepat, dan tidak tergantung musim.Penelitian ini mengidentifikasi dua bakteri endofit dari daun pepaya (Carica papaya L.), yaitu Bacillus cereus strain BFP 1 dan B. subtilis strain BFP 2, melalui analisis molekuler berbasis 16S rRNA. Kedua strain bakteri tersebut memiliki aktivitas fibrinolitik optimal pada suhu 50–60 °C dan pH 7,0–9,0. Enzim fibrinolitik ini tergolong kedalam serine protease, yang aktivitasnya dihambat oleh inhibitor seperti PMSF dan TPCK, namun aktivitasnya dapat meningkat dengan adanya penambahan ion Cu2+. Berdasarkan analisis genom, kedua menunjukkan keberadaan gen pengkode protein fibrinolitik seperti vpr, aprN, wprA, dan bpr. Gen pengkode tersebut dapat dianalisis lebih lanjut mengenai struktur proteinnya melalui rekonstruksi struktur 3D.Rekonstruksi struktur 3D gen pengkode protein memiliki resolusi belum cukup baik untuk menghasilkan model struktur yang detail, dikarenakan protein-protein tersebut belum termurnikan dengan baik, sehingga memerlukan proses pemurnian lebih lanjut. Penemuan yang didapat dari penelitian ini memberikan informasi baru tentang enzim fibrinolitik dari bakteri endofit tanaman pepaya, yang berpotensi dikembangkan sebagai agen trombolitik untuk terapi kardiovaskular.

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Endophytic microbes live in plant tissues without harming their host. They are capable of producing various bioactive enzymes and metabolites, including fibrinolytic enzymes, which are important for the therapy of cardiovascular diseases such as thrombosis. These enzymes work by activating plasminogen into plasmin or directly degrading fibrin, thereby dissolving blood clots. Compared to other sources, microorganisms as producers of fibrinolytic enzymes have several advantages, such as being easy to cultivate, having fast production, and being independent of season.

This study identified two endophytic bacteria from papaya (Carica papaya L.) leaves, namely Bacillus cereus strain BFP 1 and B. subtilis strain BFP 2, through 16S rRNA-based molecular analysis. Both bacterial strains have optimal fibrinolytic activity at 50-60°C and pH 7.0-9.0. This fibrinolytic enzyme belongs to serine protease, whose activity is inhibited by inhibitors such as PMSF and TPCK, but its activity can be increased by the addition of Cu²⁺ ions. Based on genome analysis, both showed the presence of fibrinolytic protein-coding genes such as vpr, aprN, wprA, and bpr. These coding genes can be further analyzed regarding their protein structure through 3D structure reconstruction.

Reconstruction of the 3D structure of protein-coding genes has a resolution that is not good enough to produce a detailed structural model because these proteins have not been purified properly, so they require further purification processes. The findings obtained from this study provide new information about fibrinolytic enzymes from papaya plant endophytic bacteria, which have the potential to be developed as thrombolytic agents for cardiovascular therapy.