scholarly journals Stimulation of defective Gunn-rat liver uridine diphosphate glucuronyltransferase activity in vitro by alkyl ketones

1979 ◽  
Vol 177 (3) ◽  
pp. 993-995 ◽  
Author(s):  
E N Lalani ◽  
B Burchell
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Wistar Rat ◽  
Uridine Diphosphate ◽  
Gunn Rat ◽  
Alkyl Ketone ◽  
Genetic Deficiency ◽  
Liver Homogenates ◽  
Stimulation Of

Addition of alkyl ketone (10mM) to Gunn-rat liver homogenates increased UDP-glucuronyltransferase activity towards 2-aminophenol by 10–20 fold, up to enhanced values of enzyme activity observed with similarly treated Wistar-rat liver homogenates. Alkyl ketones also activate the defective enzyme purified from Gunn-rat liver. This genetic deficiency of UDP-glucuronyltransferase activity is no longer apparent when assayed in the presence of alkyl ketones.

scholarly journals Reconstitution of purified Wistar rat liver bilirubin UDP-glucuronyltransferase into Gunn-rat liver microsomes

1982 ◽  
Vol 201 (3) ◽  
pp. 653-656 ◽  
Author(s):  
B Burchell
Keyword(s):  
Enzyme Activity ◽  
Rat Liver ◽  
Specific Activity ◽  
Liver Microsomes ◽  
Wistar Rat ◽  
Transferase Activity ◽  
Rat Liver Microsomes ◽  
Phosphatidylcholine Liposomes ◽  
Gunn Rat ◽  
Rigid Environment

1. Reconstitution of purified bilirubin UDP-glucuronyltransferase from Wistar-rat liver into Gunn-rat liver microsomes provides a better environment than phosphatidylcholine liposomes, such that the final specific activity of the Wistar-rat liver enzyme was increased up to 85 units/mg of protein. 2. Gunn- and Wistar-rat liver microsomes were equally effective for reconstitution of the purified enzyme. 3. The transferase activity does not appear to be fully expressed in the more rigid environment of foetal Wistar-rat liver microsomes. 4. These reconstitution experiments reveal a final specific activity for the purified bilirubin UDP-glucuronyltransferase consistent with the capacity of the whole rat liver to glucuronidate bilirubin and indicate that the absence of this enzyme activity in Gunn-rat liver microsomes is not due to an abnormal microenvironment.

scholarly journals The effect of phenobarbital on the submicrosomal distribution of uridine diphosphate glucuronyltransferase from rat liver

1970 ◽  
Vol 117 (2) ◽  
pp. 319-324 ◽  
Author(s):  
G. J. Mulder
Keyword(s):  
Enzyme Activity ◽  
Density Gradient ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Sucrose Density Gradient ◽  
Male Rats ◽  
Uridine Diphosphate ◽  
Triton X

1. The detergent Triton X-100 activates UDP glucuronyltransferase from rat liver in vitro six- to seven-fold with p-nitrophenol as substrate. The enzyme activity when measured in the presence of Triton X-100 is increased significantly by pretreatment of male rats with phenobarbital for 4 days (90mg/kg each day intraperitoneally). If no Triton X-100 is applied in vitro such an increase could not be shown. In all further experiments the enzyme activity was measured after activation by Triton X-100. 2. The Km of the enzyme for the substrate p-nitrophenol does not change on phenobarbital pretreatment. 3. When the microsomal fraction from the liver of untreated rats is subfractionated on a sucrose density gradient, 47% of the enzyme activity is recovered in the rough-surfaced microsomal fraction, which also has a higher specific activity than the smooth-surfaced fraction. 4. Of the increase in activity after the phenobarbital pretreatment 50% occurs in the smooth-surfaced fraction, 19% in the rough-surfaced fraction and 31% in the fraction located between the smooth- and rough-surfaced microsomal fractions on the sucrose density gradient. 5. The latency of the enzyme in vitro, as shown by the effect of the detergent Triton X-100, is discussed in relation to the proposed heterogeneity of UDP glucuronyltransferase.

scholarly journals Immunochemical comparison of UDP-glucuronyltransferase from Gunn- and Wistar-rat livers

1980 ◽  
Vol 191 (1) ◽  
pp. 155-163 ◽  
Author(s):  
P J Weatherill ◽  
S M Kennedy ◽  
B Burchell
Keyword(s):  
Rat Liver ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Wistar Rat ◽  
Rat Strains ◽  
Gunn Rat ◽  
Genetic Deficiency ◽  
Rat Livers

1. Antiserum was raised against purified Wistar-rat liver UDP-glucuronyltransferase. 2. UDP-glucuronyltransferase activities towards 4-nitrophenol, bilirubin, 1-naphthol and morphine were co-immunoprecipitated from solubilized Wistar-rat liver preparations. 3. UDP-glucuronyltransferase activities towards 1-naphthol, 2-aminophenol and 4-nitrophenol were precipitated from solubilized Gunn-rat liver preparations by this antiserum. 4. UDP-glucuronyltransferase activities towards 1-naphthol, 4-nitrophenol and bilirubin, from Wistar-rat liver, were slightly inhibited by antiserum, whereas 1-naphthol UDP-glucuronyltransferase activity from Gunn-rat livers was greatly inhibited. 5. Measurable Wistar-rat liver glucuronyltransferase activities in washed immunoprecipitates indicate that the enzyme(s) were not merely inhibited by antiserum. 6. Immunoglobulin G purified from this antiserum immunoprecipitated transferase activities towards 4-nitrophenol, bilirubin and 1-naphthol. 7. The washed immunoprecipitates from both rat strains, containing UDP-glucuronyltransferase activity, appear to be similar when analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 8. Radial-immunodiffusion studies suggest that a smaller amount of UDP-glucuronyltransferase protein is present in Gunn-rat liver than in Wistar-rat liver. 9. The significance of these results in relation to the genetic deficiency in the Gunn rat is discussed.

scholarly journals An improved assay technique for uridine diphosphate glucuronosyltransferase activity towards 5-hydroxytryptamine and some properties of the enzyme

1978 ◽  
Vol 175 (3) ◽  
pp. 1119-1124 ◽  
Author(s):  
J E A Leakey
Keyword(s):  
Rat Liver ◽  
Mouse Liver ◽  
Wistar Rat ◽  
Uridine Diphosphate ◽  
Gunn Rat ◽  
Uridine Diphosphate Glucuronosyltransferase ◽  
Membrane Perturbation ◽  
Udp Glucuronosyltransferase ◽  
Routine Assay ◽  
Assay Technique

A simplified and sensitive procedure for the routine assay of UDP-glucuronosyltransferase activity towards 5-hydroxytryptamine (serotonin) was developed and the reaction product confirmed as the O-glucuronide of this substrate. The assay was used to study some properties of this UDP-glucuronosyltransferase activity. In mouse liver activity was stimulated by membrane-perturbation procedures and by UDP-N-acetylglucosamine. In rat liver it was stimulated by digitonin, but not by diethylnitrosamine. Mouse duodenum, kidney, and lung possessed activity that was less latent than in liver. No activity was found in homogenates of brain. The activity was present in Gunn rat liver, though only one-third of that in Wistar rat liver. Cat liver contained no UDP-glucuronosyltransferase activity towards 5-hydroxytryptamine.

Substrate specificity of iodothyronine 5′-deiodinase in rat liver homogenates and its requirements of divalent cations in vitro

Life Sciences ◽  
1986 ◽  
Vol 38 (24) ◽  
pp. 2231-2238 ◽  
Author(s):  
Shinya Kobayshi ◽  
Yan Gao ◽  
Richard L. Ong ◽  
Constance S. Pittman
Keyword(s):  
Substrate Specificity ◽  
Rat Liver ◽  
Divalent Cations ◽  
Liver Homogenates

Metabolic importance of Na+/K+-ATPase activity during sea urchin development.

1997 ◽  
Vol 200 (22) ◽  
pp. 2881-2892 ◽  
Author(s):  
P Leong ◽  
D Manahan
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Sea Urchin ◽  
Sodium Pump ◽  
Sea Water ◽  
Strongylocentrotus Purpuratus ◽  
Lytechinus Pictus ◽  
Stimulation Of

Early stages of animal development have high mass-specific rates of metabolism. The biochemical processes that establish metabolic rate and how these processes change during development are not understood. In this study, changes in Na+/K+-ATPase activity (the sodium pump) and rate of oxygen consumption were measured during embryonic and early larval development for two species of sea urchin, Strongylocentrotus purpuratus and Lytechinus pictus. Total (in vitro) Na+/K+-ATPase activity increased during development and could potentially account for up to 77 % of larval oxygen consumption in Strongylocentrotus purpuratus (pluteus stage) and 80 % in Lytechinus pictus (prism stage). The critical issue was addressed of what percentage of total enzyme activity is physiologically active in living embryos and larvae and thus what percentage of metabolism is established by the activity of the sodium pump during development. Early developmental stages of sea urchins are ideal for understanding the in vivo metabolic importance of Na+/K+-ATPase because of their small size and high permeability to radioactive tracers (86Rb+) added to sea water. A comparison of total and in vivo Na+/K+-ATPase activities revealed that approximately half of the total activity was utilized in vivo. The remainder represented a functionally active reserve that was subject to regulation, as verified by stimulation of in vivo Na+/K+-ATPase activity in the presence of the ionophore monensin. In the presence of monensin, in vivo Na+/K+-ATPase activities in embryos of S. purpuratus increased to 94 % of the maximum enzyme activity measured in vitro. Stimulation of in vivo Na+/K+-ATPase activity was also observed in the presence of dissolved alanine, presumably due to the requirement to remove the additional intracellular Na+ that was cotransported with alanine from sea water. The metabolic cost of maintaining the ionic balance was found to be high, with this process alone accounting for 40 % of the metabolic rate of sea urchin larvae (based on the measured fraction of total Na+/K+-ATPase that is physiologically active in larvae of S. purpuratus). Ontogenetic changes in pump activity and environmentally induced regulation of reserve Na+/K+-ATPase activity are important factors that determine a major proportion of the metabolic costs of sea urchin development.

Uridine diphosphate glucose synthase from calf liver. Determinants of enzyme activity in vitro

Biochemistry ◽  
1975 ◽  
Vol 14 (25) ◽  
pp. 5445-5450 ◽  
Author(s):  
Peter J. Roach ◽  
Kenneth R. Warren ◽  
Daniel E. Atkinson
Keyword(s):  
Enzyme Activity ◽  
Uridine Diphosphate ◽  
Uridine Diphosphate Glucose ◽  
Diphosphate Glucose

Metabolism in vitro of n-methylamphetamine with rat liver homogenates

1977 ◽  
Vol 26 (11) ◽  
pp. 1043-1049 ◽  
Author(s):  
Ronald T. Coutts ◽  
Susan H. Kovach
Keyword(s):  
Rat Liver ◽  
Liver Homogenates

Insulin stimulus of leucine incorporation into frog liver protein

1962 ◽  
Vol 203 (4) ◽  
pp. 687-689 ◽  
Author(s):  
J. C. Penhos ◽  
M. E. Krahl
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Leucine Incorporation ◽  
Liver Protein ◽  
Amino Acid Incorporation ◽  
Insulin Effect ◽  
Acid Incorporation ◽  
Liver Slices ◽  
Stimulation Of

Slices prepared from livers of bull frogs ( Rana catesbiana), pancreatectomized and/or hypophysectomized 7 days before, were incubated 2 hr in frog Ringer-bicarbonate solution at 25 C. Incorporation of leucine-1-C14 into protein was subnormal in the pancreatectomized series. The addition of insulin in vitro, with glucose also present in the medium, produced a significant ( P < 0.01) stimulation of amino acid incorporation in the following series: livers from normal fed animals; livers from animals pancreatectomized 7 days before; and livers from animals pancreatectomized and hypophysectomized 7 days before. Neither insulin nor glucose alone gave a significant effect. These results therefore confirm and extend those obtained with rat liver slices showing that insulin can stimulate amino acid incorporation into protein when added directly to liver. The effect is relatively greatest with livers from animals pancreatectomized 7 days before; the insulin effect does not depend on the presence of the pituitary, as it is obtainable with livers from animals hypophysectomized and pancreatectomized 7 days previously.

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