Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.1.32 (phosphoenolpyruvate carboxykinase)
 4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experimentally-induced alloxan diabetes was characterized in rats by a marked increase in the blood glucose level and by a number of disturbances in the concentration of metabolites and the activity of the enzymes of carbohydrate metabolism in the liver. Stimulation of gluconeogenesis in diabetes was judged by reduction of the redox condition of free NAD- and NADP-couples, by the increase in the concentration of phosphoenolpyruvate, malic oxaloacetate and phosphoenolpyruvate carboxykinase activity of the liver. Nicotinamide in a dose of 50 mg per 100 g of body weight caused a marked reduction in the blood glucose level of diabetic rats. An increase of the [NAD+]/[NADN], [NADP+]/[NADPN] ratio, a reduction of the concentration of phosphoenolpyruvate, malate and phosphoenolpyruvate carboxylase activity pointed to the inhibition of gluconeogenesis and stimulation of glycolysis in the liver of diabetic rats given nicotinamide.
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PMID:[Hypoglycemic effect of nicotinamide in rats with alloxan diabetes]. 2 43

Periportal and perivenous hepatocytes were isolated by microdissection from lyophilized liver slices (16 micrometer) from fed and fasted rats and from a human patient. NADP/NADPH cycling was used to determine fructose-1,6-bisphosphatase activity in the isolated hepatocytes (10 ng dry weight). The periportal hepatocytes contain 3 times as much fructose-1,6-bisphosphatase activity as the perivenous hepatocytes. A 24 h fast led to two-fold increase in the activity in the periportal hepatocytes and a four-fold increase in the perivenous hepatocytes. Fructose-1,6-bisphosphatase parallels closely with the key enzyme phosphoenolpyruvate carboxykinase, and therefore can be considered a suitable marker for gluconeogenic capacity.
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PMID:Liver cell heterogeneity. The distribution of fructose-bisphosphatase in fed and fasted rats and in man. 2 36

1. N10-Formyltetrahydrofolate dehydrogenase was purified to homogeneity from rat liver with a specific activity of 0.7--0.8 unit/mg at 25 degrees C. The enzyme is a tetramer (Mw = 413,000) composed of four similar, if not identical, substrate addition and give the Km values as 4.5 micron [(-)-N10-formyltetrahydrofolate] and 0.92 micron (NADP+) at pH 7.0. Tetrahydrofolate acts as a potent product inhibitor [Ki = 7 micron for the (-)-isomer] which is competitive with respect to N10-formyltetrahydrofolate and non-competitive with respect to NADP+. 3. Product inhibition by NADPH could not be demonstrated. This coenzyme activates N10-formyltetrahydrofolate dehydrogenase when added at concentrations, and in a ratio with NADP+, consistent with those present in rat liver in vivo. No effect of methionine, ethionine or their S-adenosyl derivatives could be demonstrated on the activity of the enzyme. 4. Hydrolysis of N10-formyltetrahydrofolate is catalysed by rat liver N10-formyltetrahydrofolate dehydrogenase at 21% of the rate of CO2 formation based on comparison of apparent Vmax. values. The Km for (-)-N10-folate is a non-competitive inhibitor of this reaction with respect to N10-formyltetrahydrofolate, with a mean Ki of 21.5 micron for the (-)-isomer. NAD+ increases the maximal rate of N10-formyltetrahydrofolate hydrolysis without affecting the Km for this substrate and decreases inhibition by tetrahydrofolate. The activator constant for NAD+ is obtained as 0.35 mM. 5. Formiminoglutamate, a product of liver histidine metabolism which accumulates in conditions of excess histidine load, is a potent inhibitor of rat liver pyruvate carboxylase, with 50% inhibition being observed at a concentration of 2.8 mM, but has no detectable effect on the activity of rat liver cytosol phosphoenolpyruvate carboxykinase measured in the direction of oxaloacetate synthesis. We propose that the observed inhibition of pyruvate carboxylase by formiminoglutamate may account in part for the toxic effect of excess histidine.
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PMID:Inhibitory effects of histidine and their reversal. The roles of pyruvate carboxylase and N10-formyltetrahydrofolate dehydrogenase. 3 73

The enzymes of carbon dioxide heterotrophic fixation were studied in six strains of coryneform bacteria belonging to the genera Arthrobacter, Brevibacterium, Corynebacterium and Nocardia. All of the strains were found to contain PEP (phosphoenolpyruvate) carboxylase (EC 4.1.1.31), NADP or NAD dependent malic enzymes (EC 1.1.1.38--40). Pyruvate carboxylase (EC 6.4.1.1) was found only in three strains of coryneforms: Brevibacterium ammoniagenes, Corynebacterium aquaticum and Nocardia erythropolis. PEP carboxykinase (EC 4.1.1.32) was detected in Brevibacterium ammoniagenes and Nocardia erythropolis. PEP carboxytransphosphorylase (EC 4.1.1.38) was found only in Brevibacterium ammoniagenes. These data suggest that carboxylation of C3-acids is one of the essential pathways in some coryneforms supplying the citric acid cycle with the products of glycolysis. The composition and the level of carboxylation enzymes reflect the ecological characteristics of the organisms rather than their taxonomical relations.
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PMID:[Carboxylation enzymes of coryneform bacteria]. 11 47

1. Measurements are presented of the activity and intracellular distribution of phosphoenolypruvate carboxykinase, pyruvate carboxylase and NADP-malate dehydrogenase in rat, guinea-pig and rabbit liver and kidney cortex, together with previously obtained measurements of these enzymes in adipose tissue. 2. In all three tissues pyruvate carboxylase activity was greatest in the rat and lowest in the rabbit. 3. Guinea pig and rabbit were very similar to each other with respect to the extramitochondrial-mitochondrial distribution of phosphoenolpyruvate carboxykinase in all three tissues. 4. NADP-malate dehydrogenase was present in all three tissues in the rat, present in kidney cortex and adipose tissue in the guinea pig and absent from all tissues examines in the rabbit.
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PMID:The activities and intracellular distribution of nicotinamide-adenine dinucleotide phosphate-malate dehydrogenase, phosphoenolpyruvate carboxykinase and pyruvate carboxylase in rat, guinea-pig and rabbit tissues. 23 92

Yeast mutant lacking proteinase B activity have been isolated [Wolf, D. H. and Ehmann, C. (1978) FEBS Lett. 92, 121--124]. One of these mutants (HP232) is characterized in detail. Absence of the vacuolar localized enzyme is confirmed by checking for proteinase B activity in isolated mutant vacuoles. Defective proteinase B activity segregates 2:2 in meiotic tetrads. The mutation is shown to be recessive. Mutant proteinase B activity is not only absent against the synthetic substrate. Azocoll, but also against the physiological substrate pre-chitin synthetase, cytoplasmic malate dehydrogenase and fructose-1,6-bisphosphatase. The mutant shows normal vegetative growth, a phenomenon not consistent with the idea that proteinase B might be the activating principle of chitin synthetase zymogen in vivo. Fluorescence microscopy shows normal chitin insertion. Enzymes underlying carbon-catabolite inactivation in wild-type cells (a mechanism proposed to be possibly triggered by proteinase B) such as cytoplasmic malate dehydrogenase, fructose-1,6-bisphosphatase, phosphoenolpyruvate carboxykinase and isocitrate lyase, are inactivated also in the mutant. NADP-dependent glutamate dehydrogenase, which is found to be inactivated in glucose-starved wild-type cells, proceeds normally in the mutant. Mutant cells show more than 40% reduced protein degradation under starvation conditions. Sporulating diploids, homozygous for proteinase B absence, also exhibit an approximately 40% reduced protein degradation as compared to homozygous wild-type diploids or diploids heterozygous for the mutant gene. The time of the appearance of the first ascospores of diploid cells, homozygous for proteinase B deficiency, is delayed about 50% and sporulation frequency is reduced to about the same extent as compared to homozygous wild-type diploids or diploids heterozygous for the mutant gene.
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PMID:Studies on a proteinase B mutant of yeast. 38 14

The dynamics of label distribution was studied in the products of 14CH3OH assimilation by the cells of Pseudomonas gazotropha Z-1156. Substances to be first detected were glycolate, glycine and those of the chromatogram "start" spot. Later, the radioactivity was detected in phosphorylated compounds and glycerate. Cell extracts of Ps. gazotropha Z-1156 contained ribosephosphate isomerase, phosphoribulokinase and glyceraldehyde dehydrogenase but not ribulosediphosphate carboxylase. Distribution of the label in the products of 14CH3OH assimilation and the presence of active hydroxypyruvate reductase in the extract suggest that the serine cycle is involved in methylotrophy of Ps. gazotropha Z-1156. This suggestion is confirmed by the presence of active formate dehydrogenase, phosphoenolpyruvate carboxylase, (NADP+, Mn2+)-specific isocitrate dehydrogenase, (NAD, Mg2+)-specific malate dehydrogenase, malate lyase, and isocitrate lyase. The citric acid cycle is open at the alpha-ketoglutarate dehydrogenase system. The dry biomass of Ps. gazotropha Z-1156 contains over 70% of protein.
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PMID:[Carbon assimilation pathways in the methylotrophy of Pseudomonas gazotropha]. 70 43

Pseudomonas fluorescens grown on glucose or glutamate at 1 or 20 degrees C, or on acetate at 20 degrees C, as sole carbon sources, contained both pyruvate carboxylase and phosphoenolpyruvate carboxylase. Pyruvate carboxylase was insensitive to acetyl-coenzyme A and L-aspartate, and its level in cell-free extracts was markedly dependent on the carbon source for growth, the highest specific activity being attained in glucose-grown cells. Phosphoenolpyruvate carboxylase, on the other hand, although less dependent on the nature of the carbon source,showed its highest level in acetate-grown cells; the enzyme activity required acetyl-coenzyme A and was strongly inhibited by L-aspartate. The micro-organism had, in addition, a phosphoenolpyruvate carboxykinase, which showed its highest specific activity in cells grown on acetate, and a NADP-linked malate enzyme, apparently repressed by acetate and showing its highest specific activity in glutamate-grown cells.
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PMID:CO2-fixing enzymes in Pseudomonas fluorescens. 81 91

The content of acid-soluble nucleotides was different in the cells of non-sulphur purple bacterium Rhodospirillum rubrum, growing phototrophically under anaerobic conditions and aerobically under conditions of heterotrophic nutrition. The cells of the culture growing in the darkness contained more adenylic and guanylic nucleotides, and the total of reduced and oxidized NADP. The cells of the culture growing in the light contained more FMN. The cells of the "light" and "dark" cultures contained GTP dependent phosphopyruvate carboxylase (E.C. 4.1.1.32). The cells of the "light" culture, contrary to the "dark" culture, contained also pyrophosphate dependent phosphopyruvate carboxylase (E.C. 4.1.1.38).
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PMID:[Acid-soluble nucleotides of the phototrophic bacterium Rhodospirillum rubrum during growth in light and in darkness]. 81 80

In order to assess the extent to which metabolism within the sheep placenta may influence the transfer of metabolites between mother and foetus at different stages of gestation the activities of enzymes concerned with some aspects of carbohydrate, amino acid and keton body metabolism were determined in placental cotyledons resected from ewes during the last three months of pregnancy. The activities of pyruvate kinase (EC 2.7.1.40), lactate dehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.37), ATP citrate (pro-3S)-lyase (EC 4.1.3.8), citrate (si)-synthase (EC 4.1.3.7), acetyl-CoA synthetase (EC 6.2.1.1), acetyl-CoA acetyltransferase (EC 2.3.1.9) and 3-keto acid CoA-transferase (EC 2.8.3.5) per gram wet weight cotyledon do not change during the period studied. The activities of alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.1), isocitrate dehydrogenase (NADP+) (EC 1.1.1.42), ornithine-oxoacid aminotransferase (EC 2.6.1.13) and 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) show an increase in activity between the third and fourth months of pregnancy whilst the activities of arginase (EC 3.5.3.1) and possibly pyruvate carboxylase (EC 6.4.1.1) show an increase in activity between the fourth and final months of pregnancy. Ornithine decarboxylase (EC 4.1.1.17) activity declines to one tenth of its activity during this later period. The absence of detectable activities of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) and ornithine carbamoyltransferase (EC 2.1.3.3) indicate that gluconeogenesis and urea synthesis from ammonia do not occur in the sheep placenta. It appears that the ability of the placenta to metabolise several substrates is achieved by the time the placenta reaches its maximum size at approximately 90 days.
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PMID:Enzyme activities in the sheep placenta during the last three months of pregnancy. 84 73


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