The more pure your sample is, the easier it is to interpret the results, as contaminating proteins may contribute to your overall signal in bulk measurements.

... Read more about How pure does my protein sample need to be for analysis by DSF, CD or light scattering?

The amount of protein needed will vary by method and sometimes by the mass of protein to be characterized. See Molecular Properties Protein Requirements for estimates and recommendations for the amount of protein needed for standard data collection. Read more about How much protein is needed for molecular property analysis by DSF, CD, or light scattering?

If your membrane protein has fluorescent residues (tryptophan and tyrosine), you should consider trying our Prometheus NT.plex for DSF using intrinsic protein fluorescence (NanoDSF).

However, if you wish to do conventional DSF (dye-based), please note that many hydrophobic dyes, such as Sypro Orange, cannot be used for Differential Scanning Fluorimetry of membrane proteins, dues to high background staining. However, if your membrane protein has buried cysteines, then a cysteine-reactive dye may work. BODIPY FL-cysteine can be used, since it has excitation and emission wavelengths within the standard range of many qPCR instruments, including our QuantStudio 6/7.  CPM (a courmarin derivative) was one of the earlier dyes used for this purpose, however many modern qPCR instruments no longer have excitation filters appropriate for this dye.

... Read more about Are there fluorescent dyes than can be used for Differential Scanning Fluorimetry of Membrane Proteins?