O=C(N[C@H]1C/C=C\C[C@H](CC(=O)N(CCO)Cc2ccccc2)C(=O)N[C@H](Cc2c[nH]c3ccccc23)COC1=O)OCC1c2ccccc2-c2ccccc21
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?