Table 1.

Experimental and intrinsic KIEs for Af2Sir2 catalyzed deacetylation

label of interest	remote label	KIE type	experimental KIEa,b	intrinsic KIEc
1N-15N	2,8A-3H	primary	1.024(2)	1.024(2)d
1′N-14C	2,8A-3H	primary	1.014(4)	1.014(4)
1′N-3H	8A-14C	α-secondary	1.289(1)	1.300(3)
2′N-3H	8A-14C	β-secondary	1.095(5)	1.099(5)
4′N-3H	8A-14C	γ-secondary	0.997(2)	0.997(2)
5′N-3H	8A-14C	δ-secondary	1.019(5)	1.020(5)
4′N-18O	8A-14C	α-secondary	0.985(5)	0.984(5)
2,8A-3H	8A-14C	remote	1.001 (4)	1.001(2)

^aKIE determined from at least three experiments and from correction for isotopic depletion.

^bThe number in the parenthesis represents the error in the last digit.

^cKIE determined from experimental KIE using equation 3 and corrected for commitment factors of C_r = 0.038 and KIE_eq = 1.000 except for first entry (See Supporting Information for KIEs calculated for KIE_eq = 1.100). Error to the intrinsic KIE value includes variability in the value of C_r (0.036–0.042) due to variability in the 20% conversion to products (±2%).

^dKIE determined from experimental KIE using equation 3 and corrected for commitment factors of C_r = 0.038 and KIE_eq = 1.027 (see reference for the equilibrium isotope effect of 1.027 for full dissociation of nicotinamide). Measurement of [1′_N-³H]KIE in the presence of nicotinamidase, which minimizes reverse commitment by degrading nicotinamide, gave an experimental KIE corrected for isotope depletion of but without correction for reverse commitment of 1.307(5) in agreement with the calculated intrinsic in Table 1.