- Sequence of the pckA gene of Escherichia coli K-12: relevance to genetic and allosteric regulation and homology of E. coli phosphoenolpyruvate carboxykinase with the enzymes from Trypanosoma brucei and Saccharomyces cerevisiae. Medina, V., Pontarollo, R., Glaeske, D., Tabel, H., Goldie, H. J. Bacteriol. (1990)