Abstract: Objective To purify postsynaptic density (PSD) proteins with better dissolubility. Methods The constituents of P2，synaptosome and PSD-1 were obtained by sucrose gradient centrifugation. The purity of PSD-1 protein was validated by Western blot. These soluble proteins PSD-2 were extracted from PSD-1 using the technology of membrane sequence extraction. The protein spots of PSD-1 or PSD-2 were seperated by two-dimensional gel electrophoresis(2-DE), and analyzed by the software of PDQuest in order to show the different dissolubility of PSD-1 or PSD-2. Results The results of Western blot showed that the postsynaptic marker PSD-95 were positive staining in P2, synaptosome and PSD-1, but the presynaptic marker synaptophysin was not seen in PSD-1. There were 286±25 protein spots in the electrophoregram of PSD-1, 720±17 protein spots in the electrophoregram of PSD-2, and the difference of these numbers was significant （P<0.01）. Conclusions Pure PSD proteins can be obtained and dissolved easily by the method of sucrose gradient centrifugation plus membrane sequence extraction.

Key words: postsynaptic density, sucrose gradient centrifugation, membrane sequence abstraction, two-dimensional gel electrophoresis