Excitation spectra of 2-AB-taxol in the presence (solid curve) and absence
(dashed curve) of tubulin in PMEG buffer. Tubulin was polymerized with
2-AB-taxol prior to acquisition of the spectrum. Background fluorescence
due to tubulin polymer was examined by polymerizing tubulin with taxol.
The background fluorescence was minimal and has been subtracted from the
spectrum. The concentrations of 2-AB-taxol and tubulin were
30 M and 10
M,
respectively. The emission wavelength was 450 nm.