Abstract:
Xanthine oxidase is molybdenum and iron-containing flavoprotein, catalyzing the final oxidation stage of purines and
oxidative transformation of pterins and some aliphatic and aromatic aldehydes. Despite the importance of this enzyme, the
distribution of xanthine oxidase in traditional household animal’s milk and tissues is unknown. Formerly, we have found
most of the xanthine oxidase molecules in animal milk are inactive because of a lack of molybdenum. Ovine milk was
processed by inserting in vivo molybdenum (tungsten) into drinking water. We gave opposite dates in the presence of tungsten
too. Heating the milk of animals at 80 °C for 5 minutes in the presence of molybdenum and cysteine led to a sharp increase
of xanthine oxidase and its associated – nitrate reductase and nitrite reductase activities. The change of xanthine oxidase and
its associated activities were examined by spectrophotometry after treatment. It was established that metal ions added in
drinking water for animals have an impact on enzyme activities. The activity is formed in the ovine liver even in the absence
of exogenous molybdenum in drinking water. The associated activities of liver enzymes in the presence of molybdenum in
drinking water had slightly increased. Tungsten-containing water led to the loss of all activities of liver xanthine oxidase. It
is proposed that the liver contains a special protein involving in the incorporation of molybdenum (or tungsten) into xanthine
oxidase molecule, however, the milk or mammary gland compounds lack this protein.
