Assays

Total protein content of CSF samples was measured by Bradford assay (BioRad, Feldkirchen, Germany)and 10μg per sample were proteolysed by the commercially available in-StageTip-NHS kit (PreOmics GmbH, Martinsried, Germany) according to the manufacturer's protocol. Briefly, CSF was reduced and alkylated and incubated for 3 hrs at 37°C with Lys-C and trypsin. Resulting peptides were dried for short term storage at -80°C. Prior to measurement, peptides were resuspended in 2% acetonitrile and 0.5% ...