Purification and characterization of recombinant pyruvate dehydrogenase kinases from pea and soybean plants [abstract]

Abstract only availableFaculty Mentor: Dr. Douglas Randall, BiochemistryThe pyruvate dehydrogenase complex (PDC) is a large multienzyme complex catalyzing the oxidative decarboxylation of pyruvate and concomitant reduction of NAD to yield acetyl-CoA and NADH. The plant PDCs have vital roles in catabolic and anabolic metabolism. The plant complexes contain three primary components: pyruvate dehydrogenase (E1), dihydrolipoyl acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3). Additionally, mitochondrial PDC (mtPDC) contains two associated regulatory enzymes: pyruvate dehydrogenase kinase (PDK) and phospho-pyruvate dehydrogenase phosphatase. PDK catalyzes phosphorylation on the subunit of E1, resulting in inactivation of the complex. We have cloned two PDKs from soybean and recently we have cloned three PDKs from pea. cDNAs encoding soybean PDK 1 and 2 and pea PDK 1, 2 and 3 were subcloned into pET expression vector and E. coli BL21 (DE3) cells were transformed with each pET-28-H6-PDK construct. Recombinant proteins were expressed and purified by Ni-NTA agarose column chromatography to approximately 95% homogeneity. Biochemical characterization of these proteins is underway.The pyruvate dehydrogenase complex (PDC) is a large multienzyme complex catalyzing the oxidative decarboxylation of pyruvate and concomitant reduction of NAD to yield acetyl-CoA and NADH. The plant PDCs have vital roles in catabolic and anabolic metabolism. The plant complexes contain three primary components: pyruvate dehydrogenase (E1), dihydrolipoyl acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3). Additionally, mitochondrial PDC (mtPDC) contains two associated regulatory enzymes: pyruvate dehydrogenase kinase (PDK) and phospho-pyruvate dehydrogenase phosphatase. PDK catalyzes phosphorylation on the a subunit of E1, resulting in inactivation of the complex. We have cloned two PDKs from soybean and recently we have cloned three PDKs from pea. cDNAs encoding soybean PDK 1 and 2 and pea PDK 1, 2 and 3 were subcloned into pET expression vector and E. coli BL21 (DE3) cells were transformed with each pET-28-H6-PDK construct. Recombinant proteins were expressed and purified by Ni-NTA agarose column chromatography to approximately 95% homogeneity. Biochemical characterization of these proteins is underway