Using CCOC(=O)CNC(=O)[C@@H](CCSC)NC(=O)OC(C)(C)C to produce CSCC[C@@H](NC(=O)OC(C)(C)C)C(=O)NCC(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.