The inhibitor of mitochondrial pyruvate transport alpha-cyano-beta-(1-phenylindol-3-yl)-acrylate was used to inhibit progressively pyruvate carboxylation by liver mitochondria from control and glucagon-treated rats. The data showed that, contrary to our previous conclusions [Halestrap (1978) Biochem. J. 172, 389-398], pyruvate transport could not regulate metabolism under these conditions. This...

We have used control analysis to quantify the distribution of control in the gluconeogenic pathway in liver cells from starved rats. Lactate and pyruvate were used as gluconeogenic substrates. The flux control coefficients of the various enzymes in the gluconeogenic pathway were calculated from the elasticity coefficients of the enzymes towards their substrates and products and the fluxes throu...

The purposes of the present studies were to test the hypotheses that lower dosages of oral pyruvate ingestion would increase blood pyruvate concentration and that the ingestion of a commonly recommended dosage of pyruvate (7 g) for 7 days would enhance performance during intense aerobic exercise in well-trained individuals. Nine recreationally active subjects (8 women, 1 man) consumed 7, 15, an...

The kinetics of pyruvate phosphorylation by rabbit skeletal muscle pyruvate kinase (EC 2.7.1.40) has been studied with a coupled assay using P-enolpyruvate carboxylase (EC 4.1.1.31) and malate dehydrogenase (EC 1.1.1.37). The reaction sequence is (See journal for formula). Although the equilibrium of the pyruvate kinase reaction by itself strongly favors pyruvate production, the over-all equili...

The investigation of the substrate specificity of the pyruvate dehydrogenase complex from Escherichia coli allows a description of the binding region of pyruvate. Substrate analogs with electronegative substitutions in the methyl group show a strong competitive inhibition of the overall reaction of the pyruvate dehydrogenase complex. The most efficient inhibitor is fluoropyruvate which has a mo...

Linn et al. (Linn, T. C., Pettit, F. H., and Reed, L. J. (1969) Proc. Natl. Acad. Sci. U. S. A. 62, 234-241) have shown that purified preparations of pyruvate dehydrogenase complex can be inactivated by phosphorylation and reactivated by dephosphorylation. The present study shows that these processes also take place in rat liver mitochondria. In addition, we have compared such changes with poss...

Linn et al. (Linn, T. C., Pettit, F. H., and Reed, L. J. (1969) Proc. Natl. Acad. Sci. U. S. A. 62, 234-241) have shown that purified preparations of pyruvate dehydrogenase complex can be inactivated by phosphorylation and reactivated by dephosphorylation. The present study shows that these processes also take place in rat liver mitochondria. In addition, we have compared such changes with poss...

Although many investigators have studied the effects of pyruvate and glucose on alcohol metabolism, there is still disagreement as to what effect. they have on the rate of alcohol oxidat.ion. Jacobsen (1) discussed t.he various reports in which the results vary from no effect of pyruvate, inhibition by pyruvate or glucose, or an actual increase in the rate of alcohol oxidation by pyruvate or gl...

Spatial organization of metabolic enzymes allows substrate channeling, which accelerates processing of intermediates. Here, we investigated the effect of substrate channeling on the flux partitioning at a metabolic branch point, focusing on pyruvate metabolism in Saccharomyces cerevisiae. As a platform strain for the channeling of pyruvate flux, PYK1-Coh-Myc strain was constructed in which PYK1...