Proteins and aggregates of proteins
We have studied the mobilities of a number of proteins and their aggregates in air, N2 and CO2. A DMA-MS spectrum for lysozyme is shown in the figure [reference 5 in Publications]. Interpreting the measured mobilities as if corresponding to a sphere colliding inelastically with the gas, yields protein densities near 0.95 g/cm3 for a wide range of proteins and their aggregates [reference 6 in Publications]. Larger densities are found for proteins with symmetric structures, whose mobility is more directly related to their surface area, such as the GroEL tetradecamer.