COC(=O)[C@@H](NC(=O)N(Cc1ccccc1)C[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)OC(C)(C)C)C(C)C)C(C)C
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?