Figure 2. k_cat and K_{m, NAD} for SIRT1, SIRT2, SIRT3, and SIRT6 deacylation reactions.

A, k_cat, inset: k_cat for acetylated substrate plotted separately for clarity; Calculated k_cat values determined from non-linear regression fits to Michaelis-Menten shown below (n ≥ 3, ± standard deviation). *Estimate for SIRT3 resulting from inability to saturate reaction with NAD⁺. B, K_m for NAD⁺, Calculated K_{m, NAD} values determined from non-linear regression fits to Michaelis-Menten shown below. *Estimate for SIRT3, **K_{m, NAD} with acetylated peptide for SIRT6 was not measured due to prohibitively high peptide substrate necessary to saturate the reaction (n ≥ 3, ± standard deviation of mean).