. Author manuscript; available in PMC: 2010 Apr 8.

Published in final edited form as: J Am Chem Soc. 2009 Apr 8;131(13):4685–4694. doi: 10.1021/ja808346y

Table 1.

Intrinsic KIEs^a of PfOPRT and HsOPRT and computationally matched KIEs^b.

		PfOPRT KIEs		HsOPRT KIEs
Isotopically labeled OMP	KIEs type	Intrinsic	Calcd.	Intrinsic	Calcd.
[1′-³H] + [5′-¹⁴C]	α-secondary	1.261 ± 0.014	1.335	1.199 ± 0.015	1.330
[1′-¹⁴C] + [4′-³H]	primary	1.034 ± 0.002	1.034	1.035 ± 0.003	1.035
[2′-³H] + [5′-¹⁴C]	β-secondary	1.116 ± 0.006	1.142	1.129 ± 0.009	1.140
[1, 3-¹⁵N₂, 5′-¹⁴C] + [4′-³H]	primary	1.028 ± 0.003	1.025	1.025 ± 0.005	1.025
[3-¹⁵N, 5′ ¹⁴C] + [4′-³H]	β-secondary	0.997 ± 0.003	1.004	0.993 ± 0.002	1.004
[1, 3-¹⁵N₂, 1′-¹⁴C] + [4′-³H]	primary	1.068 ± 0.003	1.060	1.076 ± 0.005	1.061
[4′-³H] + [5′-¹⁴C]	γ-secondary	0.974 ± 0.003	0.972	0.962 ± 0.002	0.972
[5′-³H₂] + [5′-¹⁴C]	δ-secondary	1.013 ± 0.012	1.019	1.019 ± 0.002	1.018

Intrinsic KIEs were obtained by correcting for remote label KIEs and for forward commitment factors. Experimental KIEs ^x(V/K) and intrinsic KIEs ^xk are within experimental errors due to the small commitment factors. Each KIE was measured with at least 5 replicates.

Computationally matched KIEs were established from the Gaussian 98 transition state structures optimized to the family of intrinsic isotope effects. The calculated KIEs compare the bond frequencies from substrate and optimized transition states using the ISOEFF98 program.