Journal of Lipid Research, Vol 38, 2374-2379, Copyright © 1997 by Lipid Research, Inc.
Quantitative determination of thiolipids in organic solution, in membranes, and on HPTLC plates
S Zellmer, J Lasch and U Rothe
Martin-Luther-Universitat Halle-Wittenberg, Institut fur Physiologische Chemie, Halle, Germany.
In the presence of ortho-phthalaldehyde and glucosamine, thiolipids form
fluorescent isoindole derivatives. This reaction can be used to quantify
single- and double-chain mercaptans in membranes (liposomes) and micellar
solutions. The lower detection limit is 100 pmol. In addition, the assay
allows the detection of 1.9 nmol thiolipids on HPTLC plates and the
fluorescence signal is stable for days. A minor modification of the
commonly used DTNB (Ellman's) assay allows the quantification of thiolipids
in organic solutions at a concentration down to 3 nmol.