IN VITRO EVALUATION OF THE FIBRINOLYTIC AND TOXICITY PROFILE OF A PROTEASE FROM STREPTOMYCES PARVULUS DPUA 1573 ISOLATED FROM AMAZONIAN LICHENS

Resumo

Introduction: Thrombosis is one of the main causes of cardiovascular diseases, with
blood clots being responsible for events such as acute myocardial infarction and stroke.
Fibrinolytic enzymes, particularly those of microbial origin, have shown promise due to
their effectiveness in degrading fibrin and their feasibility for large-scale production.
Among them, the strain Streptomyces parvulus DPUA 1573, isolated from lichens in the
Brazilian Amazon, demonstrated high fibrinolytic potential, drawing interest as a
potential antithrombotic agent. Objective: To obtain and characterize a fibrinolytic
enzyme from Streptomyces parvulus DPUA 1573 with potential use as an
antithrombotic agent. Methods: The enzyme was produced by submerged fermentation,
purified using an aqueous two-phase system, and evaluated through in vitro assays for
thrombolytic, fibrinogenolytic, amidolytic, anticoagulant, cytotoxic, and hemolytic
activities using human plasma, tumor cells, and erythrocytes. Results: The enzyme
showed preferential partitioning of protease to the PEG-rich top phase. The crude
extract and the pre-purified fibrinolytic protease exhibited thrombolytic degradation of
41.47% and 52.98%, respectively. Additionally, the protease displayed amidolytic
activity through degradation of the Aα, Bβ, and γ chains of fibrinogen, being classified
as a chymotrypsin-like serine protease. In vitro anticoagulant assays showed a slight
prolongation of prothrombin time and partial thromboplastin time, with no effect on
thrombin time. The enzyme also showed no hemolytic activity in the blood
biocompatibility assay. Cytotoxicity testing against MDA-MB-231 and J774.A1 cells
demonstrated 80% cell viability. Conclusion: These findings suggest that the
fibrinolytic enzyme from Streptomyces parvulus DPUA 1573 holds potential for the
development of a novel antithrombotic drug candidate..