Table 2.

Kinetic isotope effects for the TcUP-catalyzed arsenolysis of uridine

Heavy uridine	Light uridine	Type of KIE	Experimental KIE	Intrinsic KIE	Predicted KIE
1′-3H	5′-14Ca	α – Secondary	1.103±0.004	1.132±0.005	1.126
1′-14C	5′-3H2	Primary	1.080±0.003b	1.103±0.004	1.109
5′-14C,2′-2H	5′-3H2	β – Secondary	1.067±0.003b,c	1.086±0.004	1.080
5′-14C,1,3-15N	5′-3H2	Primary and β – Secondary	1.027±0.003b	1.034±0.004	1.027
5′-14C,3-15N	5′-3H2	β – Secondary	1.003±0.002b	1.004±0.003	1.002
5′-14C,1-15N	–	Primary	1.024±0.004d	1.030±0.005	1.025
5′-3H2	5′-14C	δ – Secondary	1.032±0.002	1.041±0.003	1.058

^aThe remote 5′-¹⁴C KIE is assumed to be unity.

^bExperimental values corrected for remote 5′-³H₂ KIE according to the equation $\text{KIE}={\text{KIE}}_{\text{obs}}\times 5^{\prime }-{{}^3\text{H}}_2\text{KIE}$.

^cExperimental values corrected for ²H content according to the equation $\text{KIE}=({\text{KIE}}_{\text{obs}}-1+\text{F})/\text{F}$, where F is the fraction of ²H in the substrate.

^dExperimental values corrected for 3-¹⁵N KIE according to the equation KIE = KIE_obs/3-¹⁵N KIE.