The completion of the yeast genome project enables an analysis of various phenomena for a whole eukaryotic genome. We aimed at characterizing a full spectrum of target genes for a transcription activator, and specifically characterized putative targets for GCN4 in the budding yeast. The results suggest that about 1% of the genes are regulated by GCN4 and that these genes code for proteins involved in amino-acid and nucleotide metabolism. Our analysis proposes that, when enough data about the binding nature of a transcription factor exists, it is possible to identify its putative targets and also to try and assign a physiological role for this transcription factor.