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Ionization Constants pKa of Cardiolipin.

Olofsson, Gerd LU and Sparr, Emma LU (2013) In PLoS ONE 8(9).
Abstract
Cardiolipin is a phospholipid found in the inner mitochondrial membrane and in bacteria, and it is associated with many physiological functions. Cardiolipin has a dimeric structure consisting of two phosphatidyl residues connected by a glycerol bridge and four acyl chains, and therefore it can carry two negative charges. The pKa values of the phosphate groups have previously been reported to differ widely with pKa1 = 2.8 and pKa2 = 7.5-9.5. Still, there are several examples of experimental observations from cardiolipin-containing systems that do not fit with this dissociation behavior. Therefore, we have carried out pH-titration and titration calorimetric experiments on two synthetic cardiolipins, 1,1',2,2'-tetradecanoyl cardiolipin, CL... (More)
Cardiolipin is a phospholipid found in the inner mitochondrial membrane and in bacteria, and it is associated with many physiological functions. Cardiolipin has a dimeric structure consisting of two phosphatidyl residues connected by a glycerol bridge and four acyl chains, and therefore it can carry two negative charges. The pKa values of the phosphate groups have previously been reported to differ widely with pKa1 = 2.8 and pKa2 = 7.5-9.5. Still, there are several examples of experimental observations from cardiolipin-containing systems that do not fit with this dissociation behavior. Therefore, we have carried out pH-titration and titration calorimetric experiments on two synthetic cardiolipins, 1,1',2,2'-tetradecanoyl cardiolipin, CL (C14∶0), and 1,1',2,2'-tetraoctadecenoyl cardiolipin, CL (C18∶1). Our results show that both behave as strong dibasic acids with pKa1 about the same as the first pKa of phosphoric acid, 2.15, and pKa2 about one unit larger. The characterization of the acidic properties of cardiolipin is crucial for the understanding of the molecular organization in self-assembled systems that contain cardiolipin, and for their biological function. (Less)
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author
organization
publishing date
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Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
8
issue
9
publisher
Public Library of Science
external identifiers
  • wos:000324408400016
  • pmid:24058458
  • scopus:84884169039
ISSN
1932-6203
DOI
10.1371/journal.pone.0073040
language
English
LU publication?
yes
id
13deca65-7584-4dc1-b91c-42f5a0c5720c (old id 4065496)
date added to LUP
2013-11-14 11:23:48
date last changed
2019-04-23 02:43:47
@article{13deca65-7584-4dc1-b91c-42f5a0c5720c,
  abstract     = {Cardiolipin is a phospholipid found in the inner mitochondrial membrane and in bacteria, and it is associated with many physiological functions. Cardiolipin has a dimeric structure consisting of two phosphatidyl residues connected by a glycerol bridge and four acyl chains, and therefore it can carry two negative charges. The pKa values of the phosphate groups have previously been reported to differ widely with pKa1 = 2.8 and pKa2 = 7.5-9.5. Still, there are several examples of experimental observations from cardiolipin-containing systems that do not fit with this dissociation behavior. Therefore, we have carried out pH-titration and titration calorimetric experiments on two synthetic cardiolipins, 1,1',2,2'-tetradecanoyl cardiolipin, CL (C14∶0), and 1,1',2,2'-tetraoctadecenoyl cardiolipin, CL (C18∶1). Our results show that both behave as strong dibasic acids with pKa1 about the same as the first pKa of phosphoric acid, 2.15, and pKa2 about one unit larger. The characterization of the acidic properties of cardiolipin is crucial for the understanding of the molecular organization in self-assembled systems that contain cardiolipin, and for their biological function.},
  articleno    = {e73040},
  author       = {Olofsson, Gerd and Sparr, Emma},
  issn         = {1932-6203},
  language     = {eng},
  number       = {9},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {Ionization Constants pKa of Cardiolipin.},
  url          = {http://dx.doi.org/10.1371/journal.pone.0073040},
  volume       = {8},
  year         = {2013},
}