Investigation of PSMA3 in brains of B6 mice

The PSMA3 (Proteasome subunit alpha type-3) protein was identified by ligand affinity chromatography in brain specimens (frontal cortex and hippocampus) of 6-month-old, non-transgenic B6 mice, as a protein which interacts with CPD57 (4-(4-fluorophenyl)-6-(hydroxymethyl)-2-methyl-pyridine-3-carboxamide). Proteins from brain specimens were solubilized and subjected to ligand affinity chromatography applying an affinity matrix with covalently coupled CPD57. After overnight incubation at 4 °C and washing steps to remove unbound proteins, bound proteins were eluted from the ligand affinity matrix and separated by SDS-PAGE. The ligand affinity matrix with covalently coupled CPD57 enriched a protein in the range of 25-30 kDa. The protein band was cut out and subjected to identification by nano-LC-ESI-MS/MS.