The Isolation, Characterization, and Sequence of the Pyruvate Kinase Gene of Saccharomyces Cerevisiae

The Saccharomyces cerevisiae gene encoding the glycolytic enzyme pyruvate kinase has been isolated by complementation of a pyk mutant with DNA from a wild type yeast genomic library. Pyruvate kinase enzyme activity is 20-fold higher in the transformant compared to the parental strain and is glucose inducible. The cloned gene has been localized by hybridization of DNA fragments to yeast poly(A+) RNA and by complementation of the mutant defect with select subclones. A DNA sequence of 2885 nucleotides encoding a protein of 499 amino acids is reported. A polypeptide chain of 34 residues of the deduced yeast amino acid sequence closely resembles a peptide sequence at the ADP binding site of bovine muscle pyruvate kinase. The 5' end of the pyruvate kinase mRNA has been mapped and starts within the DNA sequence CAAG at -38 to -27 nucleotides upstream from the first ATG. We note that the sequence PyAAPu in this region appears to be a common consensus site for yeast RNA polymerase II transcriptional starts.