Hepatotoxicity of ricin, saporin or a saporin immunotoxin: xanthine oxidase activity in rat liver and blood serum

1996 ◽  
Vol 427 (5) ◽  
Author(s):  
M.G. Battelli ◽  
L. Buonamici ◽  
L. Polito ◽  
A. Bolognesi ◽  
F. Stirpe
Keyword(s):  
Blood Serum ◽  
Xanthine Oxidase ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Xanthine Oxidase Activity ◽  
Rat Liver And Blood

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
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