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. Author manuscript; available in PMC: 2008 Aug 1.
Published in final edited form as: Arch Biochem Biophys. 2007 Apr 5;464(1):36–47. doi: 10.1016/j.abb.2007.03.016

Table 5.

Quantitative interpretation of 13C and 18O IEs using the standard kinetic model (Scheme 1E).

13Keq3 18Keq3 k3/k2 k5/k4 13C FFa Bond Orderb Calc’d./Exptl.13C IE (%)c (V/K)/[E]ok1 [E]ok1 (%)
OxDCd 1.021 1.016 0.7 4.0 0.963 1.16 (1.14) 1.2/1.5 0.375 100
R92K 1.017 1.011 2.4 2.6 0.968 1.22 (1.22) 0.7/1.0 0.636 1
a

Fractionation factor for 13C at pH 4.2 calculated from the standard kinetic model for the OxDC-catalyzed reaction as described previously [4].

b

Bond orders are based on the results of BEBOVIB calculations [36] as reported previously [4]. Values in parentheses are the bond orders calculated on the basis of 18O fractionation factors (not shown here). nd – not computed.

c

13C IEs are calculated for the reaction at pH 4.2 using values of 13Keq3, 13k3, 13k5, k3/k2, k5/k4 computed from observations at pH 5.7. Experimental IEs are those observed at pH 4.2.

d

Measurements for wild type OxDC have been reported previously [4] and are included here for ease of comparison.