Comparison of ultrafiltration units for proteomic and N-glycoproteomic analysis by the filter-aided sample preparation method.

The filter-aided sample preparation (FASP) method allows gel-free processing of biological samples solubilized with detergents for proteomic analysis by mass spectrometry. In FASP detergents are removed by ultrafiltration, and after protein digestion peptides are separated from undigested material. Here we compare the effectiveness of different filtration devices for analysis of proteomes and glycoproteomes. We show that Microcon and Vivacon filtration units with nominal molecular weight cutoffs of 30,000 and 50,000 (30 and 50k, respectively) are equally suitable for FASP, whereas Microcon 30k units are most appropriate for mapping of N-glycosylation sites. The use of filters with these relatively large cutoffs facilitates depletion of detergents.