Journal article
pK values of the ionizable groups of proteins
Protein science, Vol.15(5), pp.1214-1218
05/01/2006
DOI: 10.1110/ps.051840806
PMCID: PMC2242523
PMID: 16597822
Abstract
We have used potentiometric titrations to measure the pK values of the ionizable groups of proteins in alanine pentapeptides with appropriately blocked termini. These pentapeptides provide an improved model for the pK values of the ionizable groups in proteins. Our pK values determined in 0.1 M KCl at 25°C are: 3.67±0.03 (α-carboxyl), 3.67±0.04 (Asp), 4.25±0.05 (Glu), 6.54±0.04 (His), 8.00±0.03 (α-amino), 8.55±0.03 (Cys), 9.84±0.11 (Tyr), and 10.40±0.08 (Lys). The pK values of some groups differ from the Nozaki and Tanford (N&T) pK values often used in the literature: Asp (3.67 this work vs. 4.0 N&T); His (6.54 this work vs. 6.3 N&T); α-amino (8.00 this work vs. 7.5 N&T); Cys (8.55 this work vs. 9.5 N&T); and Tyr (9.84 this work vs. 9.6 N&T). Our pK values will be useful to those who study pK perturbations in folded and unfolded proteins, and to those who use theory to gain a better understanding of the factors that determine the pK values of the ionizable groups of proteins.
Details
- Title: Subtitle
- pK values of the ionizable groups of proteins
- Creators
- Richard L. Thurlkill - Texas A&M University SystemGerald R. Grimsley - Texas A&M University SystemJ. Martin Scholtz - Texas A&M UniversityC. Nick Pace - Texas A&M University
- Resource Type
- Journal article
- Publication Details
- Protein science, Vol.15(5), pp.1214-1218
- DOI
- 10.1110/ps.051840806
- PMID
- 16597822
- PMCID
- PMC2242523
- NLM abbreviation
- Protein Sci
- ISSN
- 0961-8368
- eISSN
- 1469-896X
- Publisher
- Cold Spring Harbor Laboratory Press
- Language
- English
- Date published
- 05/01/2006
- Academic Unit
- Research Administration; Pharmaceutical Sciences and Experimental Therapeutics; Biochemistry and Molecular Biology; Chemistry
- Record Identifier
- 9984293081002771
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