Electrochemical determination of heme-linked pKa values and the importance of using fluoride binding in heme proteins.

Autor: Cerda JF; Department of Chemistry, Saint Joseph's University, Philadelphia, PA 19131, USA. Electronic address: jcerda@sju.edu., Roeder MH, Houchins DN, Guzman CX, Amendola EJ, Castorino JD, Fritz AL
Jazyk: angličtina
Zdroj: Analytical biochemistry [Anal Biochem] 2013 Dec 01; Vol. 443 (1), pp. 75-7. Date of Electronic Publication: 2013 Aug 23.
DOI: 10.1016/j.ab.2013.08.016
Abstrakt: The ultraviolet-visible (UV-vis) spectroelectrochemical measurements of heme proteins in the presence of a heme-bound fluoride ion can be used as a probe for heme-linked ionizations of acid-base groups in the heme pocket. A detailed study of the pH dependence of the midpoint potential of skeletal horse myoglobin (Mb) with a heme-bound fluoride ion (Mb-F) reveals how protonation of the distal histidine (H64) changes the redox properties of the protein with a determined pKa of 5.3. In addition, fluoride binding in myoglobin provides a stabilization of -1.9 kcal/mol of the ferric Mb-F relative to ferric Mb without fluoride.
(Copyright © 2013 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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