Question

Human immunodeficiency virus 1 (HIV-1) encodes a protease (MW 21,500 g/mol) that is essential for the assembly and maturation of the virus. The protease catalyzes the hydrolysis of a heptapeptide substrate with a k_cat of 1000 s^-1 and a K_m of 0.075 M.

a) Calculate V_max (M/s) for substrate hydrolysis when HIV-1 protease is present at 0.20 mg/mL. Give your answer in the format 5.4 E -6 (a hypothetical example) with 2 sig figs -- do not show units.

When -C(O)NH- of the heptapeptide is replaced by -CH₂NH-, the resulting derivative cannot be cleaved by HIV-1 protease and acts as an inhibitor. Under the same experimental conditions as in part (a), but in the presence of 2.5 μM inhibitor, V_max is 9.3 × 10^-3 M s^-1. What kind of inhibition is occurring?

competitive inhibition

non-competitive inhibition

uncompetitive inhibition

none of these

Answer 1