Effects of pyruvate on pyruvate dehydrogenase kinase of rat heart
Sensitivity of rat heart pyruvate dehydrogenase kinase (PDHK) to pyruvate inhibition was tested under various conditions using pyruvate dehydrogenase complex (PDC) in mitochondria (mPDC) and in a high speed precipitate of whole tissue homogenates (hPDC). In the latter preparation pyruvate in the range of concentration 1–10 mM caused increasing inhibition of PDHK when the enzyme was prepared from animals fed ad libitum but had no effect when the enzyme was prepared from 48 h starved animals. Similar behaviour was observed in mPDC from fed and starved animals when rotenone was present in the incubation medium. When carbonyl cyanide m-chlorophenylhydrazone (CCCP) instead of rotenone was present, pyruvate at 1 mM concentration stimulated PDHK from hearts of fed animals but was without effect at 10 mM. When mPDC or PDC from hearts of starved animals was incubated at 30°C for 30 min, inhibition of PDHK by pyruvate was restored.
Key wordspyruvate pyruvate dehydrogenase kinase heart
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- 6.Randle PJ: Fuel selection in animals. Biochem SocTrans 14: 799–806, 1986Google Scholar
- 12.Cockburn BN, Coore, HG: Starvation reduces pyruvate phosphate phosphatase activity in rat kidney. Mol Cell Biochem, 1995Google Scholar
- 14.Baxter MA: The regulation, by phosphorylation, of the pyruvate dehydrogenase complex in lactating rat mammary gland [dissertation]. Birmingham, England: University of Birmingham, 1979Google Scholar