Pyruvate kinase (Pyk1) levels influence both the rate and direction of carbon flux in yeast under fermentative conditions.

Yeast phosphofructo-1-kinase (Pf1k) and pyruvate kinase (Pyk1) are allosterically regulated enzymes that catalyse essentially irreversible reactions in glycolysis. Both the synthesis and activity of these enzymes are tightly regulated. To separate experimentally the control of Pf1k and Pyk1 synthesis from their allosteric regulation, a congenic set of PFK1, PFK2 and PYK1 mutants was constructed in which these wild-type coding regions were driven by alternative promoters.