Activation of Uridine Diphosphate Glucuronyltransferase in Guinea-pig Liver Microsomal Fractions by Phospholipase C or Mechanical Fragmentation

1974 ◽  
Vol 2 (5) ◽  
pp. 937-940 ◽  
Author(s):  
C. BERRY ◽  
A. STELLON ◽  
T. HALLINAN
Keyword(s):  
Guinea Pig ◽  
Phospholipase C ◽  
Uridine Diphosphate ◽  
Pig Liver ◽  
Mechanical Fragmentation ◽  
Guinea Pig Liver

Reduced Levels of Uridine Diphosphate Glucose Pyrophosphorylase Activity in Fetal and Neonatal Human and Guinea Pig Liver

Neonatology ◽  
1989 ◽  
Vol 56 (3) ◽  
pp. 174-180
Author(s):  
G. Vaca ◽  
L.P. Castro-Félix ◽  
C. Medina ◽  
M.D. Medina ◽  
R. Blancarte ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Uridine Diphosphate ◽  
Pig Liver ◽  
Uridine Diphosphate Glucose ◽  
Diphosphate Glucose ◽  
Guinea Pig Liver

scholarly journals The properties of uridine diphosphate glucuronyltransferase(s) which catalyse the synthesis of steroid glucuronides in microsomal fractions from guinea-pig liver

1976 ◽  
Vol 157 (3) ◽  
pp. 667-673 ◽  
Author(s):  
D Zakim ◽  
D A Vessey
Keyword(s):  
Guinea Pig ◽  
Glucuronic Acid ◽  
Large Family ◽  
Uridine Diphosphate ◽  
Bivalent Metal ◽  
Pig Liver ◽  
Bivalent Metal Ions ◽  
Triton X ◽  
Related Proteins ◽  
Guinea Pig Liver

The properties of the UDP-glucuronyltransferase(s) of guinea-pig liver that catalyse the synthesis of steroid glucuronides were examined. There are many similarities between apparently different substrate-specific forms of these enzymes in that all are activated by bivalent metal ions, and all contain at least 2 thiol groups important for enzyme activity. On the other hand, there are significant differences between the enzymes conjugating steroids and those conjugating non-steroids. Only the latter are activated by UDP-N-acetylglucosamine, which enhances their relatively poor affinity for UDP-glucuronic acid. The steroid-conjugating forms of UDP-glucuronyltransferase are not activated by UDP-N-acetylglucosamine and have relatively high apparent affinities for UDP-glucuronic acid. The rate of glucuronidation of testosterone was inhibited by treatment with phospholipase A. Treatment with cholate or Triton X-100 did not enhance the rates of glucuronidation of any steroid tested. The data indicate several similarities between different forms of UDP-glucuronyltransferase, suggesting that there is a large family of related proteins. At the same time there are important differences in the parameters that modulate the rates of different glucuronidation reactions.

Enzymatic degradation and partial biosynthetic reconstitution of microsomal and mitochondrial membranes

1979 ◽  
Vol 57 (10) ◽  
pp. 1237-1244 ◽  
Author(s):  
L. Stuhne-Sekalec ◽  
N. Z. Stanacev
Keyword(s):  
Cytochrome C ◽  
Guinea Pig ◽  
Phospholipase C ◽  
Phospholipase D ◽  
Mitochondrial Membranes ◽  
Original Activity ◽  
Pig Liver ◽  
Cytochrome C Reductase ◽  
Guinea Pig Liver ◽  
Nadph Cytochrome C Reductase

Guinea pig liver microsomal and mitochondrial membranes were degraded with phospholipase C and D followed by partial biosynthetic reconstitution. Activities of phosphatidylinositol synthetase in microsomal membranes and NADPH – cytochrome c reductase were almost completely lost after phospholipase C and D treatment; almost complete restoration of the original activity was achieved after biosynthesis of phosphatidylcholine in degraded microsomes, but was not reparable after biosynthesis of cytidinediphosphodiglycerides (CDP-diglycerides). The mitochondrial biosynthesis of polyglycerophosphatides was completely retained after degradation of these membranes with phospholipase C, but after similar treatment with phospholipase D, only about one-quarter of the original activity remained, the relative composition of polyglycerophosphatides being significantly different. The activity of NADPH – cytochrome c reductase of microsomes represented about 76% of the originalactivity after phospholipase C treatment, but only ~1% after treatment with phospholipase D. Although this activity could not be restored with CDP-diglyceride synthesis, it was restored to about 75% of the original activity after the biosynthesis of phosphatidylcholine in these fragments. These and additional experimental findings are discussed in terms of the relation between structural organization of lipids and proteins and enzymatic activities of membrane-bound phospholipid-synthesizing enzymes in microsomal and mitochondrial membranes isolated from guinea pig liver.

scholarly journals Effect on uridine diphosphate glucuronyltransferase activity of depleting and restoring phospholipids to guinea-pig liver microsomal preparations

1976 ◽  
Vol 154 (3) ◽  
pp. 783-785 ◽  
Author(s):  
C S. Berry ◽  
M Caldecourt ◽  
T Hallinan
Keyword(s):  
Guinea Pig ◽  
Uridine Diphosphate ◽  
Pig Liver ◽  
Conformationally Constrained ◽  
Guinea Pig Liver ◽  
Do So

Phospholipid depletion substantially inhibited the maximum demonstrable activities of the forward (glucuronidation) and reverse reactions of UDP-glucuronyltransferase towards p-nitrophenol in guinea-pig liver microsomal preparations. Dispersions of liver phospholipids restored activity, whereas non-phospholipid amphipaths failed to do so effectively. These results suggest that the system is probably phospholipid-dependent rather than conformationally constrained by phospholipids.

scholarly journals The phospholipid-dependence of uridine diphosphate glucuronyltransferase. Phospholipid depletion and re-activation of guinea-pig liver microsomal enzyme

1977 ◽  
Vol 163 (1) ◽  
pp. 117-124 ◽  
Author(s):  
A B Graham ◽  
D T Pechey ◽  
K C Toogood ◽  
S B Thomas ◽  
G C Wood
Keyword(s):  
Guinea Pig ◽  
Degradation Products ◽  
Active Form ◽  
Gel Filtration ◽  
Transferase Activity ◽  
Uridine Diphosphate ◽  
Pig Liver ◽  
Highly Active ◽  
Microsomal Membranes ◽  
Guinea Pig Liver

More than 80% of the phospholipid component of guinea-pig liver microsomal membranes (prepared with 154mM-KCl) was removed by treatment with phospholipase A followed by extraction of the lysophosphatides and fatty acids produced with albumin. Delipidation strongly inactivated the highly active UDP-glucuronyltransferase of these preparations and activity was restored by mixtures of phosphatidylcholine and lysophosphatidylchlone. However, small quantities of lysophosphatides were still associated with the delipidated fractions after extraction with albumin and might have influenced the inactivation and re-activation observed. To eliminate these uncertainties, microsomal proteins and phospholipids were separated by gel filtration on Sephadex G-150 in the presence of cholate. This technique also strongly inactivated the enzyme but did not generate membrane-active phospholipid degradation products. High transferase activity was again restored to the delipidated protein by choline glycerophosphatides. These results confirm the view that the fully active form of microsomal UDP-glucuronyltransferase is phospholipid-dependent.

Die Bedeutung der Homogenisationsart und -intensität für die Größe und Konstanz der Sauerstoffaufnahme von Meerschweinchen-Leberhomogenat / The Influence of Mode and Intensity of Homogenization on the Absolute Value and Stability of Oxygen Consumption of Guinea Pig Liver Homogenates

1977 ◽  
Vol 32 (11-12) ◽  
pp. 908-912 ◽  
Author(s):  
H. J. Schmidt ◽  
U. Schaum ◽  
J. P. Pichotka
Keyword(s):  
Oxygen Uptake ◽  
Guinea Pig ◽  
Measuring Time ◽  
Pig Liver ◽  
Absolute Value ◽  
Modified Method ◽  
Simultaneous Measurements ◽  
Liver Homogenates ◽  
The Absolute ◽  
Guinea Pig Liver

Abstract The influence of five different methods of homogenisation (1. The method according to Potter and Elvehjem, 2. A modification of this method called Potter S, 3. The method of Dounce, 4. Homogenisation by hypersonic waves and 5. Coarce-grained homogenisation with the “Mikro-fleischwolf”) on the absolute value and stability of oxygen uptake of guinea pig liver homogenates has been investigated in simultaneous measurements. All homogenates showed a characteristic fall of oxygen uptake during measuring time (3 hours). The modified method according to Potter and Elvehjem called Potter S showed reproducible results without any influence by homogenisation intensity.

Precision-cut Guinea-pig Liver Slices as a Tool for Studying the Toxicity of Volatile Anaesthetics

1990 ◽  
Vol 18 (1_part_1) ◽  
pp. 191-199
Author(s):  
Hanan N. Ghantous ◽  
Jeanne Fernando ◽  
Scott E. Morgan ◽  
A. Jay Gandolfi ◽  
Klaus Brandel
Keyword(s):  
Guinea Pig ◽  
Rank Order ◽  
Normal Liver ◽  
Liver Slice ◽  
Volatile Anaesthetics ◽  
Pig Liver ◽  
Liver Slices ◽  
Guinea Pig Liver ◽  
Krebs Henseleit Buffer

Cultured precision-cut liver slices retain normal liver architecture and physiological biochemical functions. Hartley male guinea-pig liver slices have proven to be a good model for studying the biotransformation and toxicity of halothane. This system was used to evaluate the biotransformation and toxicity of different volatile anaesthetics (halothane, enflurane, isoflurane and sevoflurane), and compare their effects to those of new anaesthetics (desflurane). Liver slices (250–300μm thick) were incubated in sealed roller vials, containing Krebs Henseleit buffer at 37°C under 95% O2:5% CO2 atmosphere. Volatile anaesthetics were delivered by volatilisation after pre-incubation for 1 hour to produce a constant concentration in the medium. Production of the metabolites, trifluroacetic acid and fluoride ion, was measured. Intracellular potassium ion content, protein synthesis and secretion were determined as indicators of viability of the slices. The rank order of biotransformation of anaesthetics by the liver slices was halothane >sevoflurane>isoflurane and enflurane>desflurane. The rank order of hepatotoxicity of these anaesthetics was halothane>isoflurane and enflurane>sevoflurane and desflurane. Halothane is the anaesthetic which is metabolised furthest and has the most toxic effect, while desflurane is the least metabolised anaesthetic and has the least toxicity. This in vitro cultured precision-cut liver slice system appears to be suitable for studying the biotransformation of volatile anaesthetics and correlating its role in the resulting toxicity.

scholarly journals Exolytic hydrolysis of toxic plant glucosides by guinea pig liver cytosolic beta-glucosidase.

1992 ◽  
Vol 267 (20) ◽  
pp. 14027-14032
Author(s):  
V Gopalan ◽  
A Pastuszyn ◽  
W R Galey ◽  
R.H. Glew
Keyword(s):  
Guinea Pig ◽  
Pig Liver ◽  
Beta Glucosidase ◽  
Toxic Plant ◽  
Hydrolysis Of ◽  
Guinea Pig Liver
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