ADHP is a fluorogenic peroxidase substrate (λ_ex=530 nm, λ_em=590 nm). In Vitro: To obtain the parameters K_m and k_cat for Compound I, two independent methods are used. Initially, the oxidation of ADHP using the injector functionality built-in to the fluorescence plate reader is studied. The auto-injector dispenses the H₂O₂ to initiate the reaction, as a means of generating a set of progress curves. Analysis for MPO-mediated oxidation of ADHP gives a K_m of 31±4 μM and the k_cat of 186± 6 s⁻¹.The k_obs also increases over the experimental range of ADHP concentrations from 1 to 80 μM and for the converse experiment holding substrate constant over 3 to 45 nM MPO. The apparent second order rate constant obtain from the slope of k_obs against ADHP concentration K^app_on is 2.1±0.2 mM/s^[1].