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. Author manuscript; available in PMC: 2011 Feb 1.
Published in final edited form as: Biochim Biophys Acta. 2009 Aug 11;1804(2):422. doi: 10.1016/j.bbapap.2009.08.003

Table 2.

Rate constants kB for proton transfer in dehydration and pKa values for proton donor and acceptor in variants of HCA II.a

Enzyme Orientation of
His64		 pKa ZnH2O pKa His64 kB
(µs−1)
1 Y7F in 7.0 6.0 3.9
2 N62L in 6.0 6.0 0.2
3 N62A in 6.5 6.2 0.4
4 N62V in 5.9 5.9 0.35
5 Wild type in/out 6.8 7.2 0.8
6 N62T in/out 7.0 7.0 0.4
7 N67L out 6.0 7.5 0.2
8 N62D out 7.6 8.4 0.04
a

Uncertainties in the values of the pKa are generally ± 0.1, the standard errors in kB are generally less than 20%. The data for Y7F, N67L and wild type are from ref [22]; the data for N62L, N62A, N62V, N62T, and N62D are from ref [23].