Table 1.

Kinetic parameters for conversion of Aβ1–42 to Aβ1–40 by human kidney ACE

Substrate	Product	Km (μm)	kcat (s−1)	kcat/Km (s−1·mm−1)
Aβ1–42	Aβ1–40	7	4.2	600

Aβ_1–42 peptides (0, 2.5, 5, 10, 15, 20, 25, 30, and 50 μm) were incubated at 37°C for 8 h with human kidney ACE (0.45 μm). The level of Aβ_1–40 was determined by ELISA, and K_m, k_cat, and k_cat/K_m were then calculated.