Figure 3.

ATP-independent proteasome activity is stimulated in plantaris muscles from tumor-bearing (TB) rats. (A) Representative example of specific ATP-independent proteasome activity from plantaris muscles from TB and control rats. The sharp peaks between 22–30 seconds reflect the introduction of samples into the cuvette. Measurements of ATP-independent proteasome activity were made during the steepest part of the subsequent slope over a 20 second window. (B) Plantaris, but not soleus muscles, displayed increased relative proteasome activity due to the presence of the tumor. These data are expected considering that the soleus muscle was resistant to tumor-induced atrophy (Figure 2). N = 6/group. *, Significantly different from control rats (p ≤ 0.05).