Study of human chromosomes. IV. Labeling of chromosomal proteins with the amino group specific fluorescent reagent fluorescamine.

We describe a method for labeling chromosomal proteins with an amino-group-specific fluorescent reagent, fluorescamine. Chromosomes thus labeled appear either as uniformly fluorescent or as haloes in structure depending on the proteins remaining after treatment with acid-alcohol fixation. Using fluorescamine as a probe, we demonstrate that there is a substantial loss of labeled proteins during the chromosomal preparation and also during the trypsin treatment used in the banding of chromosomes.