Figure 6.

Specific chymotrypsin-like proteasomal activities in the extracts of soluble and insoluble fractions of brains of wild-type and sandy mice. The proteasome activity assay was performed using the Proteasome-Glo Assay System with the substrate for chymotrypsin-like activity (Promega). The soluble and insoluble fractions of wild-type and sdy mouse brains (P14–15) were extracted, quantified, and diluted in assay buffer with equal concentration. Ten micrograms of each sample was used and incubated with Proteasome-Glo substrate mix with or without specific proteasome inhibitor (AdaAhx3L3VS) in a 96-well plate for 60 min at RT, followed by luminescence measurement with a plate reader. The specific proteasomal activity was calculated as follows: specific proteasomal activity = total peptidase activity (no inhibitor) – non-specific peptidase activity (with inhibitor). The activities in the soluble or insoluble fraction are given as percentages of the mean activity of the WT. Student’s two-tailed t test was used for statistical analysis. n = 3; assay performed in triplicate; ***p < 0.001, compared with wild-type.