Integrated enthalpy curves of pArg, pLys, and pOrn interaction with pAsp and pGlu. pLys and pOrn bound to (a) pAsp and (b) pGlu with an endothermic enthalpy while pArg bound both negative amino acid homopolymers with exothermic enthalpy and significantly greater binding constant. Data points are the experimental data while the line is added as a guide for the eye and is not the model fit of the data