CN[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H](C)C(=O)NCc1cccc2ccccc12)C(C)C.O=CO
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?