A summary of the measured pK values of the ionizable groups in folded proteins |
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Authors: | Gerald R Grimsley J Martin Scholtz C Nick Pace |
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Affiliation: | 1. Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, College Station, Texas 77843;2. Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843 |
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Abstract: | We tabulated 541 measured pK values reported in the literature for the Asp, Glu, His, Cys, Tyr, and Lys side chains, and the C and N termini of 78 folded proteins. The majority of these values are for the Asp, Glu, and His side chains. The average pK values are Asp 3.5 ± 1.2 (139); Glu 4.2 ± 0.9 (153); His 6.6 ± 1.0 (131); Cys 6.8 ± 2.7 (25); Tyr 10.3 ± 1.2 (20); Lys 10.5 ± 1.1 (35); C‐terminus 3.3 ± 0.8 (22) and N‐terminus 7.7 ± 0.5 (16). We compare these results with the measured pK values of these groups in alanine pentapeptides, and comment on our overall findings. |
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Keywords: | pK values protein ionizable groups pH titration peptide model compounds NMR spectroscopy |
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