A fibrinolytic serine protease was purified from the fruiting bodies of an edible mushroom, Albatrellus confluens. The enzyme had a molecular mass of 30086.41 Da, as measured by MALDI-TOF mass spectrometry. The N-terminal amino acid sequence of the enzyme was Glu-Thr-Val-Thr-Glu-Thr-Thr-Ala -Pro-Trp-Gly-Leu-Ser- Arg-Ile. It displayed optimal activity at 50 oC and within a pH range of 8.0~10.0, suggesting that the enzyme is an alkaline protease. The enzyme was stable up to 30 oC. The enzyme displayed a strong substrate specificity for the synthetic peptide, N-Suc-Ala-Ala-Pro-Phe pNA. The enzyme activity was completely inhibited by addition of PMSF, indicating that the enzyme is a serine protease. No inhibition was observed following addition of E-64, pepstatin, or EDTA. The activity of the purified enzyme was decreased in the presence Fe ²⁺ or Co ²⁺, and the enzyme was completely inhibited by addition of Hg ²⁺. From these results, we propose that Albatrellus confluens could be used for biofunctional foods development and has potential therapeutic value for the treatment of vascular diseases.