FIG. 8.

β-Casein degradation by the 20S proteasome is stimulated by PAN. PAN and M. thermophila 20S proteasome were mixed together in a 2:1 molar ratio in 25 mM TES buffer (pH 8) with 10 mM MgCl₂, 1 mM nucleotide, and 2 mg of β-casein per ml and incubated at 55°C. The amounts of α-amino groups (grps) generated by protein hydrolysis were determined. Data presented are the averages of three separate experiments. Symbols: ●, PAN and 20S proteasome with ATP; ○, 20S proteasome with ATP; ■, PAN and 20S proteasome with ADP; □, PAN and 20S proteasome with AMP-PNP.