Figure 5.

Effect of pH on the Ability of Native and Recombinant PMC to Inhibit Papain Activity.

(A) and (B) Papain was preincubated with native and recombinant PMC either at pH 4.2 (A) or 7.2 (B) for 10 min (23°C) prior to assessing its ability to degrade BAPNA by following the increase in A₃₉₅ (p-nitroanilide production) for 30 min (see Methods). SDS-PAGE and immunoblot of wild-type (WT) and recombinant PMC-6 and PMC-567 are shown in (A) (inset). Rates of BAPNA degradation (ΔA₃₉₅, slopes) by papain as affected by PMC and pH are in Table 2. Error bars indicate ± se (n = 3).

(C) Equimolar percentage inhibition by PMC-WT, PMC-567, and PMC-6 at pH 4.2 (blue) and pH 7.2 (orange).