Enzyme activity patterns of phosphoenolpyruvate carboxykinase, pyruvate kinase, glucose-6-phosphate-dehydrogenase and malic enzyme in human liver

1990 ◽  
Vol 93 (4) ◽  
pp. 409-415 ◽  
Author(s):  
M. Wimmer ◽  
C. Luttringer ◽  
M. Colombi
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Malic Enzyme ◽  
Human Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Activity Patterns ◽  
Glucose 6 Phosphate Dehydrogenase

scholarly journals Activity of selected gluconeogenic and lipogenic enzymes in bovine rumen mucosa, liver and adipose tissue

1969 ◽  
Vol 114 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Jerry W. Young ◽  
Sylvia L. Thorp ◽  
Helen Z. De Lumen
Keyword(s):  
Enzyme Activity ◽  
Adipose Tissue ◽  
Dehydrogenase Activity ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Lipogenic Enzymes ◽  
Adipose Tissues ◽  
Cleavage Enzyme ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Enzyme Patterns

The activities of phosphoenolpyruvate carboxykinase, ‘malic enzyme’, citrate-cleavage enzyme and glucose 6-phosphate dehydrogenase were assayed in homogenates of rumen mucosa, liver and adipose tissue of cattle. Rumen mucosa cytoplasm contained activities of ‘malic enzyme’ approximately sevenfold those of phosphoenolpyruvate carboxykinase, suggesting that the conversion of propionate into lactate by rumen mucosa involves ‘malic enzyme’. Neither starvation for 8 days nor feeding with a concentrate diet for at least 3 months before slaughter produced enzyme patterns in the tissues different from those in cattle given only hay, except that the all-concentrate diet caused increased activities of glucose 6-phosphate dehydrogenase and ‘malic enzyme’ in adipose tissues. Rumen mucosa, liver and adipose tissue contained phosphoenolpyruvate carboxykinase activity. ‘Malic enzyme’ was absent in liver. Citrate-cleavage enzyme activity was present in liver and adipose tissue but was quite low in rumen mucosa. Liver contained much less glucose 6-phosphate dehydrogenase activity than rumen mucosa or adipose tissue.

scholarly journals Changes in hepatic lipogenesis during development of the rat

1967 ◽  
Vol 105 (2) ◽  
pp. 717-722 ◽  
Author(s):  
C B Taylor ◽  
E. Bailey ◽  
W Bartley
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Malic Enzyme ◽  
Female Rats ◽  
Male Rats ◽  
Acetate Incorporation ◽  
Atp Citrate Lyase ◽  
Citrate Lyase ◽  
Malic Enzyme Activity ◽  
Glucose 6 Phosphate Dehydrogenase

1. Changes in the activities of ATP citrate lyase, ‘malic’ enzyme, glucose 6-phosphate dehydrogenase, pyruvate kinase and fructose 1,6-diphosphatase, and in the ability to incorporate [1−14C]acetate into lipid have been measured in the livers of developing rats between late foetal life and maturity. 2. In male rats the activities of those systems directly or indirectly concerned in lipogenesis (acetate incorporation into lipid, ATP citrate lyase and glucose 6-phosphate dehydrogenase) fall after birth and are maintained at a low value until weaning. After weaning these activities rise to a maximum between 30 and 40 days and then decline, reaching adult values at about 60 days. ‘Malic’ enzyme activity follows a similar course, except that none could be detected in the foetal liver. Pyruvate kinase activity is lower in foetal than in adult livers and rises to slightly higher than the adult value in the post-weaning period. Fructose 1,6-diphosphatase activity rises from a very low foetal value to reach a maximum at about 10 days but falls rapidly after weaning to reach adult values at about 30 days. 3. Weaning rats on to a high-fat diet caused the low activities of acetate incorporation, ATP citrate lyase, glucose 6-phosphate dehydrogenase and pyruvate kinase, characteristic of the suckling period, to persist. ‘Malic’ enzyme and fructose 1,6-diphosphatase activities were not altered appreciably. 4. No differences could be detected in hepatic enzyme activities between males and females up to 35 days, but after this time female rats gave higher values for acetate incorporation, glucose 6-phosphate dehydrogenase activity and ‘malic’ enzyme activity. 5. The results are discussed in relation to changes in alimentation and hormonal influences.

Time-course of enzyme adaptation. I. Effects of substituting dietary glucose and fructose at constant concentrations of dietary protein

1968 ◽  
Vol 46 (12) ◽  
pp. 1459-1470 ◽  
Author(s):  
B. Szepesi ◽  
R. A. Freedland
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Dietary Protein ◽  
Malic Enzyme ◽  
Dietary Change ◽  
Phosphogluconate Dehydrogenase ◽  
Dietary Fructose ◽  
Liver And Kidney ◽  
Malic Enzyme Activity ◽  
Glucose 6 Phosphate Dehydrogenase

The effect of dietary fructose on liver, kidney, and adrenal enzymes was studied in male Sprague–Dawley rats. Dietary fructose increased relative liver and kidney sizes, liver glycogen, and liver protein. The percentage increases in relative liver and kidney sizes were independent of dietary protein, but relative liver sizes were smaller in the absence of protein.The activities of all the liver enzymes studied, except glucokinase, were increased by a 65% fructose diet containing 25% casein. The rates of increases differed between enzymes; the activities of L-α-glycerophosphate dehydrogenase and phosphoenolpyruvate carboxykinase (PEP-carboxykinase) reached almost maximum in 1 day, glucose 6-phosphatase, 6-phosphogluconate dehydrogenase, and pyruvate kinase activities reached maximum in about 2 days, and glucose 6-phosphate dehydrogenase, malic enzyme, dihydroxyacetone kinase, phosphofructose kinase, and phosphohexose isomerase required at least 3 days to reach maximum activity after the dietary change. The increases in the activities of liver fructose 1,6-diphosphatase, glucose 6-phosphate dehydrogenase, pyruvate kinase, and phosphohexose isomerase did not occur in the absence of dietary protein. The activities of liver phosphofructokinase and malic enzyme were increased equally well whether the fructose diet contained protein or not, while the increases in the activities of other enzymes were less in the absence of dietary protein.The half-life of liver malic enzyme was estimated as 3 days in the glucose to fructose dietary change and 1 day in the fructose to glucose dietary change. Since malic enzyme activity was increased by fructose feeding about threefold, the data suggest that under the conditions of the experiment fructose increased malic enzyme activity by decreasing the rate of breakdown of the enzyme.In general, kidney enzymes were affected by fructose to a lesser extent than the corresponding enzymes in liver. This was particularly significant in the case of kidney glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and malic enzyme, the activities of which were only slightly increased in kidney. The activities of these three enzymes in the adrenal glands were not increased by fructose feeding.

CYCLISCHE SCHWANKUNGEN DER AKTIVITÄTEN VON HYDROXYSTEROID-DEHYDROGENASEN IM CORPUS LUTEUM DES RINDES

1972 ◽  
Vol 69 (2) ◽  
pp. 369-384
Author(s):  
H. Brandau ◽  
L. Brandau ◽  
G. Mutzke
Keyword(s):  
Enzyme Activity ◽  
Corpus Luteum ◽  
Enzyme Activities ◽  
Optical Method ◽  
Activity Patterns ◽  
Hydroxysteroid Dehydrogenase ◽  
Corpora Lutea ◽  
Bovine Corpus Luteum ◽  
Glucose 6 Phosphate Dehydrogenase

ABSTRACT In the bovine corpora lutea periodical activities of the Δ53β-, 3β-, 17β-and 20β-hydroxysteroid dehydrogenase (OHSDH) as well as activities of glyceraldehyde-3-phosphate- and glucose-6-phosphate dehydrogenase were measured quantitatively and the alterations throughout the different stages of the cycle were studied. After homogenization of the tissue and fractionate centrifugation the enzyme activities were determined by a standardized optical method. The activities of the Δ53β-, and 3β- and 17β-OHSDH increase slowly during the first 7 days of the cycle, the maximum is reached abruptly on the 12th to 13th day of the cycle. After a striking reduction the activities decline continually to the 19th to 21st day reaching the values detected at the beginning of the cycle. The 20β-OHSDH increases slowly to the maximum on the 15th day of the cycle. Activities of the 3α-OHSDH were obtained only inconsistently. The behaviour of the activities of G6PDH was nearly identical with that of the 3β-OHSDH, while the GAPDH shows only little fluctuations of its activities. The obtained enzyme activity patterns of the maturating and high functional corpus luteum correspond to the well-known data of the biosynthetic function of the bovine corpus luteum. The changes of the amounts of progesterone and 20β-progesterol agree with the course of the activities of the 3β- resp. 20β-OHSDH.

scholarly journals Identification and Characterization ofMAE1, the Saccharomyces cerevisiae Structural Gene Encoding Mitochondrial Malic Enzyme

1998 ◽  
Vol 180 (11) ◽  
pp. 2875-2882 ◽  
Author(s):  
Eckhard Boles ◽  
Patricia de Jong-Gubbels ◽  
Jack T. Pronk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Malic Enzyme ◽  
Fold Increase ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Oxidative Decarboxylation ◽  
Mrna Levels ◽  
Malic Enzyme Activity

ABSTRACT Pyruvate, a precursor for several amino acids, can be synthesized from phosphoenolpyruvate by pyruvate kinase. Nevertheless, pyk1 pyk2 mutants of Saccharomyces cerevisiae devoid of pyruvate kinase activity grew normally on ethanol in defined media, indicating the presence of an alternative route for pyruvate synthesis. A candidate for this role is malic enzyme, which catalyzes the oxidative decarboxylation of malate to pyruvate. Disruption of open reading frame YKL029c, which is homologous to malic enzyme genes from other organisms, abolished malic enzyme activity in extracts of glucose-grown cells. Conversely, overexpression ofYKL029c/MAE1 from the MET25 promoter resulted in an up to 33-fold increase of malic enzyme activity. Growth studies with mutants demonstrated that presence of either Pyk1p or Mae1p is required for growth on ethanol. Mutants lacking both enzymes could be rescued by addition of alanine or pyruvate to ethanol cultures. Disruption of MAE1 alone did not result in a clear phenotype. Regulation of MAE1 was studied by determining enzyme activities and MAE1 mRNA levels in wild-type cultures and by measuring β-galactosidase activities in a strain carrying a MAE1::lacZ fusion. Both in shake flask cultures and in carbon-limited chemostat cultures,MAE1 was constitutively expressed. A three- to fourfold induction was observed during anaerobic growth on glucose. Subcellular fractionation experiments indicated that malic enzyme in S. cerevisiae is a mitochondrial enzyme. Its regulation and localization suggest a role in the provision of intramitochondrial NADPH or pyruvate under anaerobic growth conditions. However, since null mutants could still grow anaerobically, this function is apparently not essential.

Enzyme Activity in the Platelets of Newborn Infants

PEDIATRICS ◽  
1970 ◽  
Vol 45 (3) ◽  
pp. 472-473
Author(s):  
Frank A. Oski ◽  
Scott Murphy ◽  
Frank H. Gardner
Keyword(s):  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Newborn Infants ◽  
Phosphoglycerate Kinase ◽  
Biochemical Properties ◽  
Transaminase Activity ◽  
Glutamic Oxaloacetic Transaminase ◽  
Glucose 6 Phosphate Dehydrogenase

Platelet hexokinase, phosphofructokinase, phosphoglycerate kinase, enolase, pyruvate kinase, lactic dehydnogenase, glucose-6-phosphate, dehydrogenase, and glutamic-oxaloacetic transaminase activity was assayed in platelets from newborn infants and contrasted with those of adults. Platelet phosphofnuctokinase activity was decreased and platelet phosphoglycerate kinase and glutamic-oxaloacetic transaminase activity were elevated in the platelets of newborn infants. It would appear that certain biochemical properties of the erythrocytes of the newborn are shared by the platelets as well. The metabolic consequences of these differences remain to be explored.

scholarly journals Effects of chronic hyperinsulinaemia on hepatic enzymes involved in lipogenesis and carbohydrate metabolism in the young rat

1978 ◽  
Vol 172 (2) ◽  
pp. 327-331 ◽  
Author(s):  
K L McCormick ◽  
J A Widness ◽  
J B Susa ◽  
R Schwartz
Keyword(s):  
Pyruvate Kinase ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Liver Weight ◽  
Hepatic Enzymes ◽  
Lower Blood Glucose ◽  
Lower Blood ◽  
Cleavage Enzyme ◽  
Young Rat ◽  
Blood Glucose Concentrations

Chronic (6 days) hyperinsulinaemia in young rats produced lower blood glucose concentrations and augmented body- and liver-weight gain. The insulin-treated rats had increased hepatic activities of citrate-cleavage enzyme, ‘malic’ enzyme and high-substrate (6.6 mM-phosphoenolpyruvate) pyruvate kinase, and decreased glucose 6-phosphatase. There were no changes in activities of phosphoenolpyruvate carboxykinase, phosphofructokinase, low-substrate (1.3 mM-phosphoenolpyruvate) pyruvate kinase, glucokinase and hexokinase.

scholarly journals Acinar zonation of cytosolic but not organelle-bound activities of phosphoenolpyruvate carboxykinase and aspartate aminotransferase in guinea-pig liver

1990 ◽  
Vol 271 (2) ◽  
pp. 387-391 ◽  
Author(s):  
L Agius ◽  
D Tosh
Keyword(s):  
Enzyme Activity ◽  
Guinea Pig ◽  
Aspartate Aminotransferase ◽  
Human Liver ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Cell Populations ◽  
Similar Distribution ◽  
Subcellular Compartment ◽  
Whole Cells ◽  
Intracellular Compartmentation

In human liver, unlike in rat liver, there is no apparent acinar heterogeneity of total cellular activity of phosphoenolpyruvate carboxykinase [Wimmer, Luttringer & Columbi (1990) Histochemistry 93, 409-415]. Since the intracellular compartmentation of phosphoenolpyruvate carbonxykinase differs in rat and human liver, we examined the acinar heterogeneity of cytosolic and organelle-bound activities of this enzyme in the guinea pig, which shows a more similar intracellular compartmentation of enzyme activity to human liver than does the rat. Cytosolic phosphoenolpyruvate carboxykinase activity was higher in periportal than in perivenous hepatocytes, whereas the organelle-bound activity was similar in the two cell populations. Aspartate aminotransferase and alanine aminotransferase activities showed a similar distribution to phosphoenolpyruvate carboxykinase, with a higher cytosolic activity in periportal than in perivenous hepatocytes but a similar organelle-bound activity in the two cell populations. Data on the acinar zonation of enzymes determined in whole cells or tissue should be interpreted cautiously if the enzyme activity is present in more than one subcellular compartment.

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