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Query: EC:6.4.1.1 (pyruvate carboxylase)
 1,516 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activities of pyruvate and propionyl CoA carboxylase in chicken tissues during normal growth and biotin deficiency were investigated. In normal growing chickens, liver and kidney pyruvate carboxylase activity was high and varied with age. The activity in heart and brain was low and remained relatively constant throughout the experimental period. Propionyl CoA carboxylase activity in kidney and heart appeared to increase with age but remained unchanged in liver and brain. Biotin deficiency progressively decreased both pyruvate and propionyl CoA carboxylase activities in liver, kidney, heart and brain. Most marked effects were observed in liver and kidney.
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PMID:Activities of pyruvate and prionyl Coenzyme A carboxylase in chicken tissues during normal growth and biotin deficiency. 61 93

The authors describe an anatomical familial case of progressive infantile cerebral poliodystrophy (Alpers disease), in which the study of enzyme kinetics of hepatic pyruvate carboxylase revealed an abnormal graph reflecting a loss of activity of the enzyme with low concentrations of substrate, This is a new feature in the literature on Alpers disease, and possibly indicates one of the pathogenic mechanisms responsible in this disorder which remains mysterious, although its pathology has been clearly described.
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PMID:[Alpers' infantile cerebral poliodystrophy. A case with abnormal hepatic pyruvate carboxylase]. 61 2

A procedure is described for the partial purification of pyruvate carboxylase (pyruvate:CO2 ligase (ADP-forming), EC 6.4.1.1) from the flight muscle of the locust (Schistocerca gregaria). Characterisation of the kinetic properties of this enzyme indicates that it is activated by acetyl-CoA, is insensitive to inhibition by di- and tricarboxylic acids and exhibits an apparent Km for HCO3-(16 mM) which differs by an order of magnitude from that observed for other pyruvate carboxylases. It is suggested that activation of this locust flight muscle pyruvate carboxylase during the rest leads to flight transition may result from increases in the concentrations of pyruvate and HCO3- under these conditions.
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PMID:Partial purification and some properties of pyruvate carboxylase from the flight muscle of the locust (Schistocerca gregaria). 62 40

The reaction pathway catalysed by pyruvate carboxylase was re-examined by using two independent experimental approaches not previously applied to this enzyme. To avoid the variable stoicheiometry associated with oxaloacetate formation, the reaction rate was measured by following release of Pi. Initial velocities, when plotted as a function of varying concentrations of either MgATP2- or HCO3-, at fixed concentrations of pyruvate, gave in double-reciprocal-form families of straight intersecting lines. Further, when the reaction velocity was determined as a function of varying MgATP2- concentrations by using pyruvate, 3-fluoropyruvate and 2-oxobutyrate as alternative carboxyl-acceptor substrates, the slopes of the double-reciprocal plots were significantly different. Both results support a sequential reaction pathway.
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PMID:A reappraisal of the reaction pathway of pyruvate carboxylase. 62 48

Clofibrate was administered in the diet (0.3% w/w) for varying periods of time to normal rats. Rats were killed by decapitation and several biochemical measurements were made. Clofibrate lowered serum levels of cholesterol and triglyceride and produced a kidney hypertrophy; these effects were maximal after 3 days of feeding and persisted for 21 days. Serum clofibric acid levels were highest on the 3rd day and decreased to maintenance levels by the 7th day. Clofibrate markedly increased the activities of glucose 6-phosphatase, pyruvate carboxylase and phosphoenolpyruvate carboxykinase in kidney cortex and the synthesis of glucose from glutamate, lactate, pyruvate, glycerol and malate by kidney cortex slices. Clofibrate treatment did not affect blood pH or bicarbonate levels. It is concluded that clofibrate enhances renal gluconeogenesis in the rat and that the effect is not caused by altering acid-base balance.
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PMID:Renal gluconeogenesis in clofibrate-treated rats. 63 72

1. Blood pyruvate carboxylase (pyruvate-CO2 ligase (ADP-forming); EC 6.4.1.1; PC) activities in young chickens and turkeys given low-biotin diets supplemented with biotin at graded levels were studied in three experiments. 2. In both species PC activity was related positively to the supplemental biotin level. The relationship was sigmoid and maximum activity was attained with supplemental levels above those required to give maximal growth response. 3. Enzyme activity decreased between 2 and 4 weeks of age but remained almost constant thereafter. 4. Activity in chicks was not affected by alterations in the fat or protein content of the diet. 5. Changing poults from high to low and from low to high supplemental biotin levels resulted in reversals in the levels of enzyme activity. 6. It is concluded that blood PC activity is a promising new criterion for assessing the biotin status of young chickens and turkeys.
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PMID:Blood pyruvate carboxylase (EC 6.4.1.1) activity as a criterion of biotin status in chickens and turkeys. 63 24

The intracellular location of pyruvate carboxylase (EC 6.4.1.1), citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) in rat mammary gland was investigated by using a fractional-extraction technique. The results indicate a mitochondrial location for all three enzymes.
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PMID:The intracellular location of pyruvate carboxylase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase in lactating rat mammary gland. 64 21

The insulin and glucose responses to glucagon infusions (27 microgram/hr) were determined in sheep before and after parenteral lead treatment (6 mg/kg intravenously). Glucose production was measured by primed continuous infusion of [6-3H]glucose. Glucagon and insulin concentrations before and during glucagon infusions were not significantly different between lead treatment and control experiments. Lead administration did not affect the concentration or production of glucose in the preinfusion period. However, depressed hyperglycemia during glucagon infusion in lead treated experiments tended to be associated with decreased glucose production. The reduced glucogenic response to glucagon may be the result of reduced function of pyruvate carboxylase, a key hepatic gluconeogenic enzyme in sheep, from lead induced impairment of mitochondrial function.
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PMID:Depression of hyperglycemic response to glucagon by parenteral lead administration in sheep. 64 58

1. In isolated rat hepatocytes incubated with pyruvate, ketogenesis increased with increasing pyruvate concentrations and decreased under the influence of 1 mM-alpha-cyano-4-hydroxycinnamate, a known inhibitor of pyruvate transport. Ketogenesis from pyruvate was higher by 30% in hepatocytes prepared from starved than from fed rats. 2. With pyruvate as substrate, 2 mM-dichloroacetate had no effect on ketogenesis of starved-rat hepatocytes, but increased ketogenesis of fed-rat hepatocytes to the 'starved' value. Gluconeogenesis from pyruvate, lactate and alanine, but not from glycerol, was inhibited by dichloroacetate. Both increased ketogenesis and decreased gluconeogenesis may result from an inhibition of pyruvate carboxylase by dichloroacetate. 3. Mitochondria were rapidly isolated from incubated hepatocytes, and [3-hydroxybutyrate]/[3-oxobutyrate] ratios were measured in the mitochondrial pellet ('mitochondrial' ratios) and in whole-cell suspensions ('total' ratios). Increasing pyruvate concentrations increased mitochondrial and decreased total ratios. In the presence of pyruvate (2 to 10 mM), dichloroacetate decreased mitochondrial and increased total ratios.
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PMID:The effects of pyruvate concentration, dichloroacetate and alpha-cyano-4-hydroxycinnamate on gluconeogenesis, ketogenesis and [3-hydroxybutyrate]/[3-oxobutyrate] ratios in isolated rat hepatocytes. 65 77

Varying degrees of biotin deficiency were induced by adding freeze-dried, raw egg white to the diet of broiler chicks. Aspects of liver metabolism were studied with reference to fatty liver and kidney syndrome. Mortality was low with 11.8 g egg white/kg diet, or less, but with 17.7 g/kg or more, mortality was very high. High mortality was observed with less than 0.33 microgram biotin/g liver. Associated with low concentrations of liver biotin were substantial increases in liver weight and lipid content in starved birds. The increased liver lipid content was not observed in birds fed ad libitum. The increased liver lipid content in biotin-deficient, starved birds was not reflected in the specific activities of hepatic lipogenic enzymes or hepatic lipogenesis in vivo measured by the incorporation of tritium from 3H-labelled water into liver lipid. Biotin deficiency affected the specific activities of the biotin-requiring enzymes, pyruvate carboxylase and acetyl CoA carboxylase, differently; the latter was unaffected whereas the former decreased concomitantly with liver biotin concentration.
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PMID:Biotin deficiency and liver metabolism in relation to fatty liver and kidney syndrome. 67 52


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