As a mimic of protein, a polyampholyte-based material should be able to duplicate the properties and functions of protein. A polyampholyte that is highly sensitive to both pH and temperature under physiological conditions is obtained when 80% butylamide-terminated poly(amidoamine) dentron is grafted to the backbone of styrene and maleic anhydride. The phase separation occurs at 33.7 °C at pH = 6.20, while the transition point increases to 43.9 °C at pH = 6.30. The superior performance is the consequence of the cooperative interactions among basic, acidic, and thermoresponsive groups. The polyampholyte with a suitable isoelectric point provides a platform for the development of multifunctional materials for biomedical applications.