1BDA:
reference: Lysine 156 promotes the anomalous proenzyme activity of tPA: X-ray crystal structure of single-chain human tPA., Renatus M, Engh RA, Stubbs MT, Huber R, Fischer S, Kohnert U, Bode W, EMBO J 1997 Aug 15;16(16):4797-805. PMID: 9305622

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