Estimation of protein aggregation propensity with a melting point apparatus

A method for studying protein aggregation with an automated melting point apparatus is described. The method employs thermal ramping and can generate a series of protein aggregation curves. The midpoint aggregation curve-associated temperature (T(a)) is used to evaluate the difference between the curves where the lower T(a) value corresponds to a higher aggregation propensity. The applicability of the method was demonstrated with human interleukin-1 receptor antagonist (IL-1ra) as a protein aggregation model. The method could be employed for rapid evaluation of various factors such as mutations, buffers, and excipients influencing protein aggregation propensity under the thermal stress.