Human cellubrevin participates in 20S particle assembly and ATP-dependent disassembly. Five milligrams of HPE were incubated with NSFmyc and either with (+) or without (-) recombinant-SNAP. 20S Complex was immunoprecipitated with an anti-myc antibody cross-linked to agarose beads. The beads were harvested by centrifugation, washed in the presence of ATPγS (wash), and then incubated with ATP/Mg. The resulting supernatant was harvested (release), and the beads were then stripped with glycine (beads). The proteins were recovered by trichloroacetic acid (TCA) precipitation and analyzed by Western blotting with an anti-Hceb antibody (1/100).