3.4.23.48 Converts human Glu-plasminogen to plasmin by cleaving the Arg560-/-Val peptide bond that is also hydrolysed by the mammalian u-plasminogen activator and t-plasminogen activator. Also cleaves arginyl bonds in other proteins - - 3.4.23.48 Converts human Glu-plasminogen to plasmin by cleaving the Arg560-/-Val peptide bond that is also hydrolysed by the mammalian u-plasminogen activator and t-plasminogen activator. Also cleaves arginyl bonds in other proteins distribution of residues within the active site cleft strongly suggests that the arginine side chain of the substrate will bind in a deep, negatively charged pocket formed by Pla residues E29, D204, D206, and E217. The two valine residues C-terminal to the scissile bond will likely bind in the shallow, hydrophobic pocket located on the other side of the plane formed by the active site residues D84, H208, and the nucleophilic water molecule 718407