Using CC(C)C(=O)N[C@H](CS)C(=O)O to produce CC(C)C(=O)N[C@H](CSSC[C@@H](NC(=O)C(C)C)C(=O)O)C(=O)O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.