Induction of xanthine oxidase activity, endoplasmic reticulum stress and caspase activation by sodium metabisulfite in rat liver and their attenuation by Ghrelin

2015 ◽  
Vol 76 ◽  
pp. 27-32 ◽  
Author(s):  
Sevim Ercan ◽  
Ceren Kencebay ◽  
Goksun Basaranlar ◽  
Narin Derin ◽  
Mutay Aslan
Keyword(s):  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Xanthine Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Sodium Metabisulfite ◽  
Caspase Activation ◽  
Xanthine Oxidase Activity

scholarly journals A quantitative histochemical study of xanthine oxidase activity in rat liver using the cerium capture method in the presence of polyvinyl alcohol.

1994 ◽  
Vol 42 (8) ◽  
pp. 1091-1096 ◽  
Author(s):  
W M Frederiks ◽  
K S Bosch ◽  
R J Van den Munckhof ◽  
C J Van Noorden
Keyword(s):  
Polyvinyl Alcohol ◽  
Xanthine Oxidase ◽  
Rat Liver ◽  
Incubation Medium ◽  
Oxidase Activity ◽  
Specific Inhibitor ◽  
Semipermeable Membrane ◽  
Final Reaction Product ◽  
Final Reaction ◽  
Xanthine Oxidase Activity

A recently developed histochemical technique to demonstrate xanthine oxidase activity in milk globules of bovine mammary gland and in epithelial cells of rat small intestine using cerium ions and a semipermeable membrane was slightly modified. The semipermeable membrane method was replaced by the addition of 10% (w/v) polyvinyl alcohol to the incubation medium. This technically more simple procedure enabled detection of xanthine oxidase activity in unfixed cryostat sections of rat liver. Both methods gave qualitatively and quantitatively similar results. Activity was found in sinusoidal cells and in liver parenchymal cells, with 50% higher activity in pericentral than in periportal areas. The specificity of the reaction was proven by the generation of only small amounts of final reaction product on incubation either in the absence of the substrates hypoxanthine or oxygen or in the presence of hypoxanthine and allopurinol. Allopurinol is a specific inhibitor of xanthine oxidase activity. The amount of final reaction product, as measured cytophotometrically in rat liver, increased linearly with incubation time (15-90 min) and with section thickness (up to 12 microns). By varying the hypoxanthine concentrations, a Km value of 0.05 mM was found. Addition of dithiothreitol to the incubation medium reduced the amount of final reaction product by 85%, which was caused by conversion of reversible xanthine oxidase into xanthine dehydrogenase. This histochemical method can be used for quantitative analysis of in situ xanthine oxidase activity.

Activity and stability of rat liver xanthine oxidase in the presence of pyridine

2011 ◽  
Vol 89 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kaveh Amini ◽  
Mohammad-Hossein Sorouraddin ◽  
Mohammad-Reza Rashidi
Keyword(s):  
Thermal Stability ◽  
Enzyme Activity ◽  
Xanthine Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Enzyme Inactivation ◽  
Native Enzyme ◽  
Buffer Solution ◽  
Stability Parameters ◽  
Xanthine Oxidase Activity

In the present study, rat liver xanthine oxidase activity and its thermostability in the presence of pyridine were investigated. The activity of the enzyme was determined by following the formation of uric acid spectrophotometrically. The thermal stability of the enzyme was studied in the presence of 0.0%–2.0% of pyridine in Sorenson’s buffer. Thermal stability parameters (half-life, inactivation constant, and activation energies for enzyme inactivation), thermodynamic constants (ΔH*, ΔS*, and ΔG*) and the kinetic parameters (Km and Vmax), were determined in pyridine-free and pyridine-containing buffer solution. A dramatic reduction was observed in xanthine oxidase activity in the presence of pyridine. However, the pyridine-treated enzyme showed a marked enhancement in thermal stability compared with the native enzyme. The ΔG values for the enzyme activity in the presence of pyridine were found to be about 1.5-fold larger than that calculated for the native enzyme, indicating that the enzyme becomes kinetically more stable in the presence of pyridine. The Km value for xanthine oxidase in the presence of 0.5% pyridine increased by 4.8-fold compared with the enzyme in the pyridine-free buffer solution; however, there was 1.8-fold reduction in the Vmax value in the hydro-organic solution compared with the enzyme activity in the buffer solution. As the stability of enzymes is one of the most difficult problems in protein chemistry, this thermostability property of xanthine oxidase could be of great value in developing novel strategies to improve and expand its application in various areas.

Effects of hyperthermia on xanthine oxidase activity and glutathione levels in the perfused rat liver

1989 ◽  
Vol 4 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Joseph L. Skibba ◽  
Anna Stadnicka ◽  
John H. Kalbfleisch ◽  
Robert H. Powers
Keyword(s):  
Xanthine Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Perfused Rat Liver ◽  
Xanthine Oxidase Activity

Intensification of the xanthine oxidase activity of rat liver homogenates on storage

1968 ◽  
Vol 46 (9) ◽  
pp. 1047-1056
Author(s):  
D. G. R. Blair ◽  
B. D. McLennan
Keyword(s):  
Xanthine Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Enzyme Assay ◽  
Substrate Inhibition ◽  
Temperature Dependent ◽  
Xanthine Oxidase Activity ◽  
Aging Period ◽  
Liver Homogenates ◽  
High Concentrations

The xanthine oxidase activity of rat liver homogenates increased severalfold when the homogenates were stored (aged) at 4 °C for several days. The increase could be demonstrated by measuring xanthine oxidase activity by xanthine utilization or allantoin formation from xanthine. The increase in activity was not correlated with the concentrations of allantoin, uric acid, xanthine, or hypoxanthine in the homogenates, and, therefore, is not attributed to decrease of substrate inhibition, but its demonstration was partially inhibited by relatively high concentrations of xanthine in the enzyme-assay reaction medium.The increase in xanthine oxidase activity was temperature-dependent and was unaffected by the presence of glucose or adenosine 5′-triphosphate. Lysis of unbroken cells during the aging period and microbial contamination were not contributory. Dialysis of a fresh homogenate partially inhibited the increase in activity, but the addition of the dialysate of an aging homogenate to a dialyzed or fresh homogenate did not stimulate activity.The mechanism of the increase in xanthine oxidase activity has not been elucidated, but the fact that stimulation of the activity by methylene blue decreases as the homogenates age, suggests that the rate at which reduced xanthine oxidase is oxidized by air may increase with homogenate aging.

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