Rat epididymal fat pads were incubated in vitro at 37” in bicarbonate buffer, pH 7.4, with uniformly labeled pyruvateW. The net gas exchange, total CO:, production, O2 consumption, pyruvate utilization, lactate and glycerol production, and radioactive carbon incorporation into COZ, fatty acids, and glyceride glycerol were measured. The results were used to estimate the quantitative flow of pyru...

Pyruvate kinase (EC 2.7.1.40) is one of the key regulatory enzymes controlling glycolysis in plants and animals. It catalyzes the irreversible formation of pyruvate and ATP from phosphoenolpyruvate and ADP. In plants, pyruvate kinases can be either heteroor homotetramers depending on the source of the isozyme (Plaxton, 1989). Pyruvate kinase enzymes have been purified or partially purified from...

We have presented evidence that stimulation of pyruvate dehydrogenase, (PDH.) kinase activity by pyruvate or by acetyl-CoA is mediated through acetylation of lipoyl moieties (Cate, R. L., and Roche, T. E. (1978) J. Biol. Chem. 253,496-503). In accord with this indirect mechanism for the action of these effecters, we now find that the degree of stimulation of PDH, kinase increases with the level...

The effects of L-carnitine on 14CO2 release from [1-14C]pyruvate oxidation (an index of pyruvate dehydrogenase activity, PDH), [2-14C]pyruvate, and [6-14C]glucose oxidation (indices of the acetyl-CoA flux through citric acid cycle), and [U-14C]glucose (an index of both PDH activity and the flux of acetyl-CoA through the citric acid cycle), were studied using isolated rat cardiac myocytes. L-car...

The failure to detect an equilibrium between acetyl phosphate, a product of pyruvate cleavage, and pyruvate has been one of the poorly understood observations of the pyruvate cleavage reactions in Clostridium butyricum and in Escherichia coli (l-3), although pyruvate synthesis from acetyl phosphate was reported in the latter organism (4). In the preceding paper (5) a small incorporation of acet...

Carrier-facilitated pyruvate transport across the inner mitochondrial membrane plays an essential role in anabolic and catabolic intermediary metabolism. Mitochondrial pyruvate carrier 2 (Mpc2) is believed to be a component of the complex that facilitates mitochondrial pyruvate import. Complete MPC2 deficiency resulted in embryonic lethality in mice. However, a second mouse line expressing an N...

Acetaminophen, a common analgesic/antipyretic, is a frequent cause of acute liver failure in Western countries. The development of an effective cure against acetaminophen hepatotoxicity is crucial. Ethyl pyruvate, an ethyl ester derivative of pyruvic acid, has been identified as a possible candidate against acetaminophen hepatotoxicity in animal experiments. However, the mode of the hepatoprote...

PURPOSE To test the feasibility of hyperpolarized [1-(13) C]pyruvate magnetic resonance imaging (MRI) for noninvasive examination of guinea pig fetoplacental metabolism and nutrient transport. MATERIALS AND METHODS Seven pregnant guinea pigs with a total of 30 placentae and fetuses were anesthetized and scanned at 3T. T1 -weighted (1) H images were obtained from the maternal abdomen. An 80 mM...

Conditioned media from glial cell cultures contain low molecular weight agents which can support survival of CNS neurons in the absence of recognized protein neuronotrophic factors. A similar support is provided to CNS neurons by selected basal media, and pyruvate is the critical medium constituent responsible for their trophic competence. Eagle's basal medium, which contains no pyruvate, acqui...