Histone acetyl-transferases (HATs) seem to be key elements in the regu
lation of transcription. We have designed an enzymatic assay to quanti
fy HAT enzymatic activity. In this assay, the substrate is a peptide c
orresponding to the 24 first amino acids of histone H4 which is couple
d to biotin. After acetylation using [C-14]acetyl-CoA, the peptide is
purified on streptavidin beads and the associated radioactivity is mea
sured. This assay is sensitive, rapid and convenient.