Fluorescence stopped‐flow study of the binding of S6‐GTP to tubulin

the fluorescence emission of the Trp residue in tubulin. A fluorescence decrease can therefore be expected when the nucleotide binds to tubulin, due to the possibility of radiationless energy transfer. Using the stopped-flow, it was possible to follow the fast reactions at 25 and 35’C. During the course of this study a dissociation constant of 1.7 X lo-’ M for S6-GTP and 8.3 X lo-’ M for S6-GDP was published in an