COC(=O)CNC(=O)C(CSC(=O)OCC1c2ccccc2-c2ccccc21)NC(=O)CCC(NC(=O)OCC1c2ccccc2-c2ccccc21)C(=O)OC
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?