Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structural gene Pck-1, encoding cytosolic phosphoenolpyruvate carboxykinase (GTP) (PEPCK; EC 4.1.1.32), has been assigned to mouse chromosome 2. This assignment was made based on genomic Southern transfer of rat-mouse and hamster-mouse hybrid DNAs using a rat kidney cloned cDNA of the PEPCK gene as a probe. Conclusive evidence for the cosegregation of the PEPCK gene with mouse chromosome 2 was obtained using a monochromosomal microcell hybrid that selectively retained a Robertsonian translocation between mouse autosomes 2 and 8 and its back-selected hybrid clone.
Somat Cell Mol Genet 1985 Nov
PMID:Assignment of the gene encoding cytosolic phosphoenolpyruvate carboxykinase (GTP) to Mus musculus chromosome 2. 386 85

The administration of 2 bromo-alpha-ergocryptine, to reduce serum prolactin decreased the activity of cytosolic P-enolpyruvate carboxykinase (GTP) (EC 4.1.1.32) about 50% in both liver and mammary gland of lactating animals. Adrenalectomy had similar effects to those of bromo-alpha-ergocryptine. In contrast, there was a 50% increase in enzyme activity in the mammary gland of diabetic, lactating rats and a 10-fold increase in liver as compared with normal rats. P-enolpyruvate carboxykinase activity in mammary gland as liver is coordinately regulated by prolactin, glucocorticoids and insulin.
Mol Cell Biochem 1985 May
PMID:Effect of prolactin and glucocorticoids on P-enolpyruvate carboxykinase activity in liver and mammary gland from diabetic and lactating rats. 402 4

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
Mol Biochem Parasitol 1980 Mar
PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7

The degradation of glucose by Trypanosoma cruzi leads to the excretion of succinate. Malate dehydrogenase (MDH) participates in this process by reducing to malate the oxaloacetate synthesized by the glycosomal enzyme, phosphoenolpyruvate carboxykinase. The best coupling for these two sequential reactions would be attained if both enzymes were placed in the same subcellular compartment. The intracellular distribution of the MDH activity in epimastigotes of T. cruzi was studied by two methods. Selective disruption of cellular membranes with increasing concentrations of digitonin, indicated that trypanosomal MDH is particulate. Isopycnic centrifugation in a sucrose gradient of a large granule fraction, obtained by grinding the cells with silicon carbide, showed the presence of two MDH activities: one banding together with the glycosomal marker phosphoenolpyruvate carboxykinase, the other with the mitochondrial marker citrate synthase. Isoelectrofocusing of cell-free extracts led to the separation of two enzyme forms, with pI values of about 3.5 (MDHa) and 9.4 (MDHb). These forms had similar molecular weights (approx. 60 000) and apparent Km values, but showed a small but consistent difference in their pH optima (9.23 for MDHa and 9.05 for MDHb), and in their activation by inorganic phosphate (apparent Ka values of 33 mM and 87 mM, for MDHa and MDHb, respectively). Determination of the pH optima of the enzyme forms separated by isopycnic centrifugation suggests that the glycosomal enzyme form is MDHa, and the mitochondrial one is MDHb.
Mol Biochem Parasitol 1984 Apr
PMID:Glycosomal and mitochondrial malate dehydrogenases in epimastigotes of Trypanosoma cruzi. 637 51

Evidence is presented for the occurrence of glycosomes (organelles resembling peroxisomes) in four major species of Leishmania (viz. L. major, L.m. mexicana, L. b. braziliensis and L. donovani), based on latency as well as differential and isopycnic centrifugation studies. The enzymes involved in glycolysis; (hexokinase, phosphoglucose isomerase, phosphofructokinase, fructose-1,6-bisphosphate aldolase, triosephosphate isomerase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase); glycerol metabolism (sn-glycerol-3-phosphate dehydrogenase and glycerol kinase); carbon dioxide fixation (phosphoenolpyruvate carboxykinase and possibly malate dehydrogenase); together with an enzyme involved in the beta-oxidation of fatty acids (3-beta-hydroxybutyryl coenzyme A dehydrogenase); a key enzyme in the synthesis of ether lipids (dihydroxyacetone phosphate acyltransferase) as well as the ADP utilising enzyme adenylate kinase, were all found associated, at least in part, with a subcellular organelle which had a buoyant density in sucrose gradients of 1.21 to 1.24 g cm-3. Little variance in enzyme composition was found between the different species of Leishmania or in comparison with other members of the Trypanosomatidae, supporting the unifying principle that glycosomes are a unique characteristic of this family. The occurrence of important catabolic, anabolic and anaplerotic pathways in the glycosomes of Leishmania renders them prime targets for chemotherapy.
Mol Biochem Parasitol 1984 Oct
PMID:The occurrence of glycosomes (microbodies) in the promastigote stage of four major Leishmania species. 644 18

Glycogen content, glucose consumption and the production of metabolic end products by Calicophoron ijimai were determined under aerobic and anaerobic conditions. The major end products of fermentation were identified as lactic, acetic, propionic, isobutyric and alpha-methylbutyric acids, propionic acid predominating. The activities and properties of some of the enzymes of carbohydrate metabolism were determined. The worms showed high phosphoenolpyruvate carboxykinase, malate dehydrogenase and malate dehydrogenase (decarboxylating) but relatively low pyruvate kinase and very low lactate dehydrogenase activities. The pH optima, coenzyme, cofactor and ionic requirements of the enzymes were similar to those of other helminths. Malate dehydrogenase had an 8-fold greater affinity for oxaloacetate than malate, and was about 14 times more active for oxaloacetate reduction than malate oxidation. Phosphoenolpyruvate carboxykinase was 2.4 times more active and had a 2-fold greater affinity for phosphoenolpyruvate and dinucleotide than pyruvate kinase. The low activities of lactate dehydrogenase and pyruvate kinase but high activities of malate dehydrogenase and phosphoenolpyruvate carboxykinase suggest that anaerobic carbohydrate catabolism follows the fumarate reductase pathway.
Mol Biochem Parasitol 1984 Sep
PMID:Fermentation and the properties of some enzymes of carbohydrate metabolism in the trematode Calicophoron ijimai. 651 86

Highly purified glycosomes were isolated from Trypanosoma brucei bloodstream forms and cultured procyclic trypomastigotes. A comparison of the specific activities of glycosomal enzymes revealed that glycosomes from insect stages had decreased levels of hexokinase, phosphoglucose isomerase, phospho-fructokinase, fructose-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase, but contained increased levels of adenylate kinase, malate dehydrogenase and phosphoenolpyruvate carboxykinase. Glycosomes from bloodstream forms were almost totally devoid of the latter two activities. Comparison of the two types of glycosomes by sodium dodecylsulphate-polyacrylamide gel electrophoresis revealed that bloodstream form glycosomes contained 3 prominent polypeptides (64, 46 and 40 kDa) which were hardly detectable in insect stage glycosomes, whereas the latter contained 3 insect stage specific bands with molecular weight of 34 000, 61 000 and 77 000 and 4 additional bands with molecular weights between 94 000 and 110 000. Both types of glycosome contained the phospholipids phosphatidylcholine and phosphatidylethanolamine. Insect stage glycosomes contained in addition also phosphatidylinositol and some phosphatidylserine.
Mol Biochem Parasitol 1984 May
PMID:A comparison of the glycosomes (microbodies) isolated from Trypanosoma brucei bloodstream form and cultured procyclic trypomastigotes. 674 87

Particulate fractions obtained from Trypanosoma cruzi and Crithidia fasciculata by different procedures were subjected to isopycnic centrifugation in sucrose gradients, in order to determine the subcellular localization of phosphoenolpyruvate carboxykinase (PEPCK) in both organisms, and of malic enzyme (ME) I in T. cruzi. The more clear-cut results were obtained with T. cruzi by breaking the cells by grinding in a mortar with silicon carbide and using a gradient from 0.4 to 2.0 M sucrose, whereas with C. fasciculata, the best procedure was disruption of the cells by digitonin treatment and potter homogenization and use of a gradient from 1.1 to 2.0 M sucrose. PEPCK banded together with the glycosomal marker hexokinase in both organisms; there was a clear separation from the mitochondrial markers, oligomycin-sensitive Mg2+-APTase and citrate synthase. PEPCK showed a latency of 24% in the enriched 'glycosoma' fraction of T. cruzi. ME I from T. cruzi, on the other hand, banded together with the mitochondrial markers. These results indicate that PEPCK and ME are present in different subcellular compartments, a fact significant for the prevention of a futile cycle between C4-dicarboxylic acids and C3-monocarboxylic acids, which might take place if both enzymes functioned in the same compartment.
Mol Biochem Parasitol 1982 Sep
PMID:Subcellular localization of phosphoenolpyruvate carboxykinase in the trypanosomatids Trypanosoma cruzi and Crithidia fasciculata. 675 7

Phosphoenolpyruvate carboxykinase (EC 4.1.1.32) was detected in a particulate fraction of Trypanosoma brucei brucei procyclic culture form. It requires ADP rather than GDP for activity in the direction of carboxylation and is located in the glycosomes. Since phosphoenolpyruvate can serve to furnish ATP for glycolysis and can promote 3-phosphoglycerate or 1,3-bisphosphoglycerate formation without simultaneous alpha-glycerophosphate production, we suggest that the glycosomal phosphoenolpyruvate carboxykinase-malate dehydrogenase tandem contributes to ATP regeneration and NADH re-oxidation in the glycosome, and regulates alpha-glycerophosphate production.
Mol Biochem Parasitol 1983 May
PMID:Occurrence and role of phosphoenolpyruvate carboxykinase in procyclic Trypanosoma brucei brucei glycosomes. 687 81

Procedures have been developed for the extraction and subsequent purification of the enzyme phosphoenolpyruvate carboxykinase (GTP) (PEPCK) from Moniliformis dubius (Acanthocephala), a parasite of the rat small intestine. This is believed to be the first purification of PEPCK from an invertebrate animal. The enzyme, when purified to homogeneity as indicated by electrophoretic criteria, has a molecular weight of 73 700. Kinetic studies indicated that the enzyme had a pH optimum of 5.5 and required Mn2+ as the divalent cation. The apparent Km values determined for the substrates of the carboxylation reaction were low compared with the published values for purified PEPCK from vertebrate sources. Several competitive inhibitors were found and their Ki values determined. The possible regulation of PEPCK activity in M. dubius is discussed with reference to the observed kinetic parameters.
Mol Biochem Parasitol 1981 Feb
PMID:A study of phosphoenolpyruvate carboxykinase from Moniliformis dubius (Acanthocephala). 721 43


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>