[In vitro studies on the fixation dependent artifact formation in electron microscope autoradiography]

The binding of 14C-labeled L-fucose to bovine serum albumin by glutaraldehyde was investigated. Separation of protein-bound radioactivity from free precursor was performed either by TCA precipitation, thin layer chromatography or gel chromatography on Sephadex columns. For a positive control, [14C] fucose was replaced by [14C] leucine which has repeatedly been reported to be subjected to artifactual retention in glutaraldehyde-fixed tissue. It is shown that, under conditions where substantial amounts of free leucine are bound to albumin, radioactivity from L-[14C]fucose is not detectable in the protein fractions.