Abstract:
:Potentiometric titrations and surface potential measurements have been used to determine the intrinsic pKa values of both the carboxyl and amino groups of phosphatidylserine (PS) in mixed vesicles of PS and phosphatidylcholine (PC), and also of the amino group of phosphatidylethanolamine (PE) in mixed PE-PC vesicles. The pKa of the carboxyl group of PS in liposomes with different PS/PC lipid ratios measured by the two different methods is 3.6 +/- 0.1, and the pKa of its amino group is 9.8 +/- 0.1. The pKa of the amino group of PE in PE-PC vesicles, determined solely by surface potential measurements, is 9.6 +/- 0.1. These pKa values are independent of the aqueous phase ionic strength and of the effect of the liposome's surface potential due to the presence of these partially charged lipids.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Tsui FC,Ojcius DM,Hubbell WLdoi
10.1016/S0006-3495(86)83655-4subject
Has Abstractpub_date
1986-02-01 00:00:00pages
459-68issue
2eissn
0006-3495issn
1542-0086pii
S0006-3495(86)83655-4journal_volume
49pub_type
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