Ultrasonic Properties of Melittin Solution

Melittin undergoes structural change from monomeric random coil to tetrameric helices according to various conditions. The ultrasonic properties of melittin solution were measured as a function of the frequency, the temperature, pH and the concentration. There was no ultrasonic relaxation nor anomaly of temperature dependence. When pH was varied, ultrasonic velocity showed a significant change due to the helix-coil transition accompanied by aggregation. The concentration dependence of the ultrasonic velocity was nonlinear, from which the mechanism of the aggregation was discussed.