The PDC1 gene of Saccharomyces cerevisiae, encoding pyruvate decarboxylase was sequenced. The gene contains an open reading frame of 1647 base pairs. The codon usage shows the same strong bias as found for some other glycolytic enzymes. Transcription starts mainly at -30 and terminates 100 base pairs downstream of the termination codon. In some strains a second termination site, 46 base pairs upstream of the stop codon was observed. The function of the promoter region was analyzed by fusion to the bacterial structural gene encoding beta-lactamase (bla). On multicopy plasmid or integrated in the genome, the expression of the bla gene showed the regulation of the authentic PDC1 gene.