<prompt> The molecular weight of a protein can be determined byNative acrylamide Gel Electrophoresis PAGESodium dodecyl Sulphate h-PAGEIsoelectric focusingIon Exchange Chromatography  <response>: the molecular weight of an unknown protein can be determined by using the SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis method. Although there are some other methods i.e. analytical ultracentrifugation and light scattering for calculating the size or molecular weight MW of an unknown protein, they are not commonly used for this purpose since they use large amounts of highly purified proteins and require costly equipment. 