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Updated: Aug 25, 2026

High-Resolution Respirometry in a Small-Volume Chamber
Published on: July 25, 2025
Toward oxygen binding curves of single respiratory proteins
Wolfgang Erker1, Markus Lippitz, Thomas Basché
1Institute for Physical Chemistry, University of Mainz, Welderweg 11, Mainz 55128, Germany. erker@mail.uni-mainz.de
Abstract:
Oxygen binding curves of single molecules promise to discriminate between different models describing cooperativity because load distributions are accessible. Individual tarantula hemocyanins could be detected by fluorescence correlation spectroscopy using intrinsic tryptophan fluorescence as sensor of bound oxygen. However, imaging of immobilized proteins was not possible due to fast photo-bleaching. It is shown that tetra-methyl-carboxy-rhodamine (TAMRA), commonly used as a fluorescence label in single-molecule spectroscopy, can also be applied to monitor bound oxygen. The dye's fluorescence is quenched due to Förster energy transfer to the oxygenated active sites of hemocyanin.
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