Figure 6.

Inhibition of the human β-secretase, BACE-1. L. vannamei F4 (A) and F5 (B) were assayed for their ability to inhibit the human BACE-1 cleavage of a quenched fluorogenic peptide based on the Swedish mutation. Fluorescent emission was monitored for 90 min (λ_ex = 320 nm, λ_em = 405 nm). Data are presented as % inhibition calculated from the mean of the substrate only and containing no inhibitor controls ± SD (n = 3). The IC₅₀ of L. vannamei F4 (A; solid line, filled circles) and F5 (B; solid line, filled circles) was determined to be 4.61 μg·mL⁻¹ (R2 = 0.97) and 5.93 μg·mL⁻¹ (R² = 0.93), respectively. In contrast the IC₅₀ heparin (A and B dashed line, open circles) was ~2.43 μg·mL⁻¹ (R² = 0.93).