scholarly journals GLYCOGEN SYNTHESIS FROM URIDINE DIPHOSPHATE GLUCOSE

1961 ◽  
Vol 10 (2) ◽  
pp. 195-209 ◽  
Author(s):  
David J. L. Luck
Keyword(s):  
Liver Cell ◽  
Glycogen Content ◽  
Specific Activity ◽  
Glycogen Synthesis ◽  
High Specific Activity ◽  
Transferase Activity ◽  
Uridine Diphosphate ◽  
Structural Elements ◽  
Diphosphate Glucose ◽  
Cell Fractions

The distribution in liver cell fractions of UDPG-glycogen transferase has been studied. In fasting animals which have been refed 6 hours before sacrifice, the distribution of the enzyme in the various cell fractions can be correlated with the glycogen content of each fraction. A purified glycogen fraction has been prepared by differential centrifugation in sucrose gradients. This glycogen fraction contains vesicular structures which resemble those seen in association with glycogen deposits in the intact liver cell. In addition, the glycogen pellet contains UDPG-glycogen transferase in high specific activity. Subfractionation of the glycogen pellet separates the majority of vesicular elements from the bulk of transferase activity and glycogen. The evidence presented suggests that the presence of UPDG-glycogen transferase in the glycogen pellet is to be attributed to its binding to glycogen rather than to its association with the structural elements found in the glycogen fraction.

scholarly journals Studies on glycogen synthesis in pigeon liver homogenates. Glycogen synthesis from glucose monophosphates and uridine diphosphate glucose

1967 ◽  
Vol 105 (2) ◽  
pp. 515-519 ◽  
Author(s):  
V. N. Nigam
Keyword(s):  
Time Course ◽  
Initial Rate ◽  
Glycogen Synthesis ◽  
Uridine Diphosphate ◽  
Cytoplasmic Fraction ◽  
Uridine Diphosphate Glucose ◽  
Diphosphate Glucose ◽  
Liver Homogenates ◽  
Pigeon Liver ◽  
Glycogen Formation

Comparative time-course studies of glycogen synthesis from glucose 6-phosphate, glucose 1-phosphate and UDP-glucose show that glucose 1-phosphate forms glycogen at an initial rate faster than that obtained with glucose 6-phosphate and UDP-glucose. After 5min. the rates from glucose monophosphates are considerably slower. 2,4-Dinitrophenol decreases glycogen synthesis from both glucose monophosphates, whereas arsenate and EDTA increase glycogen synthesis from glucose 1-phosphate and inhibit the reaction from glucose 6-phosphate, galactose and galactose 1-phosphate. Mitochondria-free pigeon liver cytoplasmic fraction forms less glycogen from glucose monophosphates than does the whole homogenate. 2-Deoxyglucose 6-phosphate inhibits glycogen synthesis from glucose monophosphates. Glycogen formation from UDP-glucose is relatively unaffected by dinitrophenol, by arsenate, by EDTA, by 2-deoxyglucose 6-phosphate and by the removal of mitochondria from the whole homogenate.

Simulation study of control of hepatic glycogen synthesis by glucose and insulin

1976 ◽  
Vol 231 (5) ◽  
pp. 1608-1619 ◽  
Author(s):  
M El-Refai ◽  
RN Bergman
Keyword(s):  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Glucose Production ◽  
Mass Action ◽  
Hepatic Glycogen ◽  
Uridine Diphosphate ◽  
Extracellular Glucose ◽  
Diphosphate Glucose ◽  
Glycogen Deposition ◽  
Predicted Values

The plausibility of various hypotheses concerning the effects of glucow dynamic model of glucose metabolism in the liver. The model consisted of six compartments representing extracellular glucose, and intracellular glucose, glucose 6-phosphate, glucose 1-phosphate, uridine diphosphate glucose, obtained from literature reports, the model predicted values of intermediates which were close to those reported for the liver, sampled from fasting animals. The model predicts that glucose can generate significant glycogen deposition by engendering the inhibition of glucose-6-phosphatase, but not by mass action, glycogen synthase activation, or phosphorylase deactivation. The model predicts that, although insulin can inhibit glucose production by lowering phosphorylase and gluconeogenesis, only an insulin-mediated induction of glucokinase can account for insulin's action to potentiate the effect of glucose alone on glycogen synthesis.

NON-LETHAL ASSIMILATION AND DISTRIBUTION OF RADIOACTIVE PHOSPHORUS IN SERRATIA MARCESCENS

1964 ◽  
Vol 10 (3) ◽  
pp. 317-322 ◽  
Author(s):  
G. E. Myers ◽  
R. G. L. McCready
Keyword(s):  
Serratia Marcescens ◽  
Culture Medium ◽  
Specific Activity ◽  
Test Organism ◽  
High Specific Activity ◽  
Lethal Effect ◽  
Optimal Conditions ◽  
Radioactive Phosphorus ◽  
Lipid Fractions ◽  
Cell Fractions

Optimal conditions for non-lethal assimilation of radioactive phosphorus by Serratia marcescens have been studied. Ten microcuries or less of P32per 300 ml of medium has no significant lethal effect on the test organism. The presence of 1% w/v glucose in the culture medium stimulates phosphorus assimilation causing an increase of approximately 34%. Phosphorus assimilation over a 24 hour period increases by approximately 50% when cultures are incubated at 30 °C rather than 37 °C.The concentration of P32in the various cellular constituents has been determined at various intervals during 24 hour incubation. Incorporation of P32in the acid-soluble and lipid fractions of the cell begins almost immediately whereas there is a slight delay prior to incorporation into the R.N.A. and longer delay before incorporation into D.N.A. Sixty to 65% of the P32assimilated by the bacterial cell is incorporated into the nucleic acids. Although R.N.A. has the highest specific activity of the cell fractions studied, the phospholipid fraction also has high specific activity.

scholarly journals 6-Phosphogluconate dehydrogenase and the assay of uridine diphosphate glucose pyrophosphorylase in the cellular slime mould Dictyostelium discoideum

1972 ◽  
Vol 126 (3) ◽  
pp. 593-600 ◽  
Author(s):  
T. D. Edmundson ◽  
J. M. Ashworth
Keyword(s):  
Cell Differentiation ◽  
Dehydrogenase Activity ◽  
Dictyostelium Discoideum ◽  
Specific Activity ◽  
Uridine Diphosphate ◽  
Cellular Slime Mould ◽  
Slime Mould ◽  
Phosphogluconate Dehydrogenase ◽  
Cellular Slime ◽  
Diphosphate Glucose

1. 6-Phosphogluconate dehydrogenase activity is present in all morphogenetic stages during cell differentiation in the cellular slime mould. 2. The different ratios of 6-phosphogluconate dehydrogenase/UDP-glucose pyrophosphorylase observed during this process can render spectrophotometric assays of UDP-glucose pyrophosphorylase inaccurate. 3. The disputed occurrence of increases in specific activity of UDP-glucose pyrophosphorylase during cell differentiation in the cellular slime mould is discussed in the light of these observations.

HISTOCHEMICAL INVESTIGATION OF THE EFFECTS OF OESTROGEN, PROGESTERONE AND RELAXIN ON GLYCOGEN, AMYLOPHOSPHORYLASE, TRANSGLYCOSYLASE AND URIDINE DIPHOSPHATE GLUCOSE-GLYCOGEN TRANSFERASE IN UTERI OF MICE

1965 ◽  
Vol 32 (2) ◽  
pp. 245-257 ◽  
Author(s):  
KATHLEEN HALL
Keyword(s):  
Enzyme Activities ◽  
Glycogen Synthesis ◽  
Glandular Epithelium ◽  
Uridine Diphosphate ◽  
Phosphorylase Activity ◽  
Uridine Diphosphate Glucose ◽  
Ovariectomized Mice ◽  
Diphosphate Glucose ◽  
Arterial Muscle

SUMMARY (1) The effects of combinations of oestrogen, progesterone and relaxin on glycogen content, and on amylophosphorylase, transglycosylase and uridine diphosphate glucose-glycogen glucosyl transferase activities in the corpus uteri of intact and ovariectomized virgin mice were investigated by histochemical techniques. (2) Glycogen and the enzyme activities were localized to myometrial and arterial muscle fibres, mobilized leucocytes when present, and luminal and glandular epithelium. Transglycosylase activity was not found in glandular epithelium and no information was obtained about UDPG-glycogen synthesis in epithelium or in leucocytes; otherwise the distribution of the three activities appeared to be similar. (3) In untreated ovariectomized mice no glycogen was detected in vivo and phosphorylase activity was low. In untreated intact mice little histochemically detectable glycogen was found in myometrial muscle at any stage of the cycle and almost no UDPG-synthesized glycogen; amylophosphorylase activity appeared to be increased during pro-oestrus and oestrus. (4) Oestrogen produced increased amounts of glycogen in vivo and stimulated phosphorylase activity in both muscle layers in intact and ovariectomized mice; UDPG-glycogen synthesis was probably also increased. (5) Relaxin had no detectable effect on myometrial glycogen or on phosphorylase activity in non-primed ovariectomized mice, but both were increased when relaxin was given to oestrogen-primed ovariectomized mice or to intact mice at pro-oestrus or oestrus. Only small increases were detected in UDPG-glycogen synthesis. (6) In both intact and ovariectomized oestrogen-primed mice progesterone had a differential action on the two layers of the myometrium: it increased both glycogenolysis and phosphorylase activity in the longitudinal fibres, but inhibited phosphorylase activity in the circular fibres without resulting in glycogen synthesis in vivo. Results on UDPG-glycogen synthesis were inconclusive. Simultaneous administration of relaxin prevented the inhibitory action of progesterone on glycogen and phosphorylase activity in the circular muscle layer and UDPG-glycogen synthesis was also high in these mice. (7) No consistent effects of the hormones were detected on glycogen or enzyme activities in arterial muscle. (8) The histochemical tests visualized total phosphorylase activity but gave no information about hormonal influence on phosphorylase a and b ratios.

Galactose-1-Phosphate Uridyl Transferases Activity in Hemolysates of Newborn Infants

PEDIATRICS ◽  
1967 ◽  
Vol 39 (2) ◽  
pp. 293-294
Author(s):  
WON G. NG ◽  
WILLIAM R. BERGHEN ◽  
GEORGE N. DONNELL ◽  
JOAN E. HODGMAN
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Newborn Infants ◽  
Nicotinamide Adenine ◽  
Necessary Condition ◽  
Transferase Activity ◽  
Uridine Diphosphate ◽  
Uridine Diphosphate Glucose ◽  
Diphosphate Glucose ◽  
Normal Adults

Kabacy, et al. have shown by the uridine diphosphate glucose (UDPG) consumption assay that galactose-1-phosphate uridyl transferase (transferase) activity in hemolysates of newborn infants is significantly lower than for normal adults. Recent studies of hemolysate UDPGalactose-4-epimerase (epimerase) in newborns have suggested the possibility that the results of Kabacy, et al. may have been influenced by regeneration of UDPG by the epimerase reaction. A necessary condition for assay of transferase by UDPG consumption is that epimerase activity be negligible. We now have shown that epimerase activity in hemolysates from newborn infants is markedly elevated and, in contrast to findings with normal adults, substantial epimerase activity is present in the absence of exogenous oxidized nicotinamide adenine dinucleotide (NAD).

Sign in / Sign up

Export Citation Format

Share Document